check before: 2026-04-01
Product:
Exchange, Microsoft 365 admin center
Platform:
Online, US Instances, World tenant
Status:
Change type:
Admin impact, Feature update, Updated message
Links:
Details:
Summary:
Exchange Online's External Recipient Rate Limit (ERR) enforcement is delayed to April 2026 for new/trial tenants and October 2026 for existing tenants. The limit is 2000 external recipients within 24 hours, as a sublimit of the 10000 recipient rate limit. The change does not apply to DoD, GCC, or GCC High organizations.
Details:
Updated June 25, 2025: We have updated the content. Thank you for your patience.
Important update regarding the cloud hosted Mailbox External Recipient Rate Limit: In order to reduce the impact on customers, Microsoft has again decided to delay the rollout of the cloud hosted Mailbox External Recipient Rate Limit (MERRL) by ~six months. The MERRL will go into enforcement in April 2026 for trial tenants and new tenants if the tenant is provisioned on/after April 1st, 2026. In April 2026, the Exchange Admin Center Report will be available for tenant admins to review Sender mailbox data on external recipient volume. In October 2026, the MERRL will go into enforcement for all cloud hosted mailboxes in the WWMT environment including existing tenants.
Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn) or reach out to your Microsoft account team for further support in this journey.
Please note: We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production.
Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn) or reach out to your Microsoft account team for further support in this journey.
________________________________________
Today, we are announcing that, beginning in April 2026 (previously October 2025), Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours.
Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources.
[When this will happen:]
The new ERR limit will be introduced in 2 phases:
Phase 1 - Starting April 1, 2026, (previously October 2025) the limit will apply to cloud-hosted mailboxes of trial tenants and all tenants created after this date.
Phase 2 - Starting October 1, 2026, (previously April 2026) we will start applying the limit to cloud-hosted mailboxes of existing tenants.
Change Category:
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Scope:
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Release Phase:
Created:
2024-04-27
updated:
2025-06-26
Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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MS Urgency
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MS workload name
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MS Blog Link
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summary for non-techies**
Starting in April 2026 for new users and October 2026 for existing users, Exchange Online will limit cloud-hosted mailboxes to sending emails to a maximum of 2,000 external recipients per day, while maintaining the overall daily limit of 10,000 recipients, to prevent misuse and ensure fair use of the email system.
Direct effects for Operations**
External Recipient Rate Limit Enforcement
Limiting the number of external recipients to 2000 within 24 hours may disrupt communication for marketing and outreach efforts, leading to potential loss of business opportunities.
- roles: Marketing Manager, Sales Representative
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
Increased Internal Email Traffic
With the restriction on external emails, users may resort to sending more internal emails, potentially overwhelming internal systems and leading to performance issues.
- roles: IT Support Specialist, System Administrator
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
User Frustration and Productivity Loss
Users may experience frustration due to the inability to send emails to external recipients, leading to decreased productivity and morale.
- roles: End User, Team Leader
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
Need for Alternative Solutions
Organizations may need to invest in alternative email solutions (like Azure Communication Services) to accommodate high-volume external communications, leading to additional costs and resource allocation.
- roles: Finance Manager, IT Manager
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
Compliance and Policy Adjustments
Changes in email sending limits may require updates to compliance policies and user training, which can lead to temporary confusion and non-compliance risks.
- roles: Compliance Officer, HR Manager
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
Configutation Options**
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Opportunities**
Utilization of Azure Communication Services for High Volume Email
With the introduction of the External Recipient Rate Limit, organizations that require high-volume email sending can transition to Azure Communication Services (ACS) for Email. This will allow them to bypass the limitations imposed by Exchange Online and cater to their bulk emailing needs effectively.
- next-steps: Assess current email sending requirements and identify users or departments that frequently exceed the 2000 external recipient limit. Provide training and resources on ACS to facilitate the transition.
- roles: Marketing Team, Sales Team, Customer Support Team
- references: https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview
Implementation of Email Usage Monitoring Tools
The new reporting feature in the Exchange Admin Center will allow tenant admins to review external recipient volume. This presents an opportunity to implement monitoring tools that can analyze email sending patterns and optimize email campaigns accordingly.
- next-steps: Explore and integrate email monitoring solutions that can work alongside the Exchange Admin Center reports. Train admins on how to interpret the data for actionable insights.
- roles: IT Administrators, Marketing Team, Compliance Officers
- references: https://learn.microsoft.com/en-us/exchange/admin/reporting/reporting-in-exchange-online
Enhanced Training for Users on Email Policies
As the ERR limit is enforced, users may need guidance on how to manage their email practices to stay within the limits. Offering training sessions on best practices for email communication can enhance user experience and compliance.
- next-steps: Develop a training program that covers the new ERR limit, effective email communication strategies, and the use of ACS for bulk emailing. Schedule regular training sessions for affected teams.
- roles: Human Resources, IT Training Coordinators, Department Managers
- references: https://www.microsoft.com/en-us/microsoft-365/business/learn/
Potentional Risks**
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IT Security**
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explanation for non-techies**
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change history
| Date | Property | old | new |
| 2025-06-26 | MC Last Updated | 12/17/2024 02:23:11 | 2025-06-25T21:38:39Z |
| 2025-06-26 | MC Messages | Updated December 16, 2024: We have updated the content. Thank you for your patience.
Important update regarding the cloud hosted Mailbox External Recipient Rate Limit: After carefully considering your feedback and understanding the need for additional time to adjust, Microsoft has decided to delay the rollout of the cloud hosted Mailbox External Recipient Rate Limit (MERRL) by ~six months. The MERRL will go into enforcement in October 2025 for trial tenants and new tenants provisioned after October 1st, 2025. In October 2025, the Exchange Admin Center Report will be available for tenant admins to review Sender mailbox data on external recipient volume. In April 2026, the MERRL will go into enforcement for all tenant's cloud hosted mailboxes including existing tenants. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn), or reach out to your Microsoft account team for further support in this journey. We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn), or reach out to your Microsoft account team for further support in this journey. ________________________________________ Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. | Updated June 25, 2025: We have updated the content. Thank you for your patience.
Important update regarding the cloud hosted Mailbox External Recipient Rate Limit: In order to reduce the impact on customers, Microsoft has again decided to delay the rollout of the cloud hosted Mailbox External Recipient Rate Limit (MERRL) by ~six months. The MERRL will go into enforcement in April 2026 for trial tenants and new tenants if the tenant is provisioned on/after April 1st, 2026. In April 2026, the Exchange Admin Center Report will be available for tenant admins to review Sender mailbox data on external recipient volume. In October 2026, the MERRL will go into enforcement for all cloud hosted mailboxes in the WWMT environment including existing tenants. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn) or reach out to your Microsoft account team for further support in this journey. Please note: We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn) or reach out to your Microsoft account team for further support in this journey. ________________________________________ Today, we are announcing that, beginning in April 2026 (previously October 2025), Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting April 1, 2026, (previously October 2025) the limit will apply to cloud-hosted mailboxes of trial tenants and all tenants created after this date. Phase 2 - Starting October 1, 2026, (previously April 2026) we will start applying the limit to cloud-hosted mailboxes of existing tenants. |
| 2025-06-26 | MC Summary | Exchange Online's introduction of an External Recipient Rate Limit (ERRL) will be enforced in phases starting January 2025, with a limit of 2000 external recipients in 24 hours. The rollout for existing tenants is delayed until October 2025, with full enforcement by April 2026. DoD, GCC, and GCC High organizations are currently exempt. | Exchange Online's External Recipient Rate Limit (ERR) enforcement is delayed to April 2026 for new/trial tenants and October 2026 for existing tenants. The limit is 2000 external recipients within 24 hours, as a sublimit of the 10000 recipient rate limit. The change does not apply to DoD, GCC, or GCC High organizations. |
| 2025-06-26 | MC End Time | 02/02/2026 09:00:00 | 2026-12-31T09:00:00Z |
| 2025-06-26 | MC prepare | If you have a cloud-hosted mailbox that needs to exceed the ERR limit, you can move to Azure Communication Services for Email, which is designed specifically for high volume email sent to recipients external to your tenant.
https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview https://learn.microsoft.com/azure/communication-services/concepts/email/prepare-email-communication-resource | If you have a cloud-hosted mailbox that needs to exceed the ERR limit, you can move to Azure Communication Services for Email, which is designed specifically for high volume email sent to recipients external to your tenant.
https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview |
| 2024-12-17 | MC Messages | Updated November 15, 2024: We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production.
Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. | Updated December 16, 2024: We have updated the content. Thank you for your patience.
Important update regarding the cloud hosted Mailbox External Recipient Rate Limit: After carefully considering your feedback and understanding the need for additional time to adjust, Microsoft has decided to delay the rollout of the cloud hosted Mailbox External Recipient Rate Limit (MERRL) by ~six months. The MERRL will go into enforcement in October 2025 for trial tenants and new tenants provisioned after October 1st, 2025. In October 2025, the Exchange Admin Center Report will be available for tenant admins to review Sender mailbox data on external recipient volume. In April 2026, the MERRL will go into enforcement for all tenant's cloud hosted mailboxes including existing tenants. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn), or reach out to your Microsoft account team for further support in this journey. We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production. Please refer to the ACS email documentation (Prepare an email communication resource for Azure Communication Services - An Azure Communication Services concept article | Microsoft Learn), or reach out to your Microsoft account team for further support in this journey. ________________________________________ Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. |
| 2024-12-17 | MC Last Updated | 11/15/2024 20:06:19 | 2024-12-17T02:23:11Z |
| 2024-12-17 | MC prepare | If you have a cloud-hosted mailbox that needs to exceed the ERR limit, you can move to Azure Communication Services for Email, which is designed specifically for high volume email sent to recipients external to your tenant.
https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview | If you have a cloud-hosted mailbox that needs to exceed the ERR limit, you can move to Azure Communication Services for Email, which is designed specifically for high volume email sent to recipients external to your tenant.
https://learn.microsoft.com/azure/communication-services/concepts/email/email-overview https://learn.microsoft.com/azure/communication-services/concepts/email/prepare-email-communication-resource |
| 2024-12-17 | MC Summary | Beginning January 2025, Exchange Online will enforce a new External Recipient Rate limit of 2000 recipients per 24 hours, introduced in two phases for new and existing tenants. This limit is part of the overall 10000 Recipient Rate limit, aiming to prevent abuse of services. Organizations exceeding this limit should consider Azure Communication Services for Email. | Exchange Online's introduction of an External Recipient Rate Limit (ERRL) will be enforced in phases starting January 2025, with a limit of 2000 external recipients in 24 hours. The rollout for existing tenants is delayed until October 2025, with full enforcement by April 2026. DoD, GCC, and GCC High organizations are currently exempt. |
| 2024-11-16 | MC Messages | Updated May 31, 2024: We have made the decision to not proceed with this change for DoD or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed.
Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. | Updated November 15, 2024: We have made the decision to not proceed with this change for DoD, GCC, or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed. The External Recipient Rate Limit will only apply to WWMT/Production.
Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. |
| 2024-11-16 | MC Last Updated | 05/31/2024 21:14:17 | 2024-11-15T20:06:19Z |
| 2024-06-01 | MC Messages | Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours.
Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. | Updated May 31, 2024: We have made the decision to not proceed with this change for DoD or GCC High organizations at this time. We will communicate via Message center when we are ready to proceed.
Today, we are announcing that, beginning in January 2025, Exchange Online will begin enforcing an external recipient rate limit of 2000 recipients in 24 hours. Exchange Online does not support bulk or high-volume transactional email. We have not enforced limiting of bulk email until now, but we plan on doing so with the introduction of an External Recipient Rate (ERR) limit. The ERR limit is being introduced to help reduce unfair usage and abuse of Exchange Online resources. [When this will happen:] The new ERR limit will be introduced in 2 phases: Phase 1 - Starting January 1, 2025, the limit will apply to cloud-hosted mailboxes of all newly created tenants. Phase 2 - Between July and December 2025, we will start applying the limit to cloud-hosted mailboxes of existing tenants. |
| 2024-06-01 | MC Title | Exchange Online to introduce External Recipient Rate Limit | (Updated) Exchange Online to introduce External Recipient Rate Limit |
| 2024-06-01 | MC Last Updated | 04/27/2024 01:12:49 | 2024-05-31T21:14:17Z |
| 2024-06-01 | MC MessageTagNames | Feature update, Admin impact | Updated message, Feature update, Admin impact |
Last updated 6 months ago ago
