check before: 2026-01-31
Product:
Microsoft 365 admin center, Teams, Teams Premium
Platform:
Online, World tenant
Status:
Change type:
Admin impact
Links:
Details:
Summary:
Teams Premium organizations using custom HTML templates for Teams Events emails must reference a verified custom domain in Microsoft 365 to ensure delivery and prevent spoofing. Enforcement began January 31, 2026. Default templates are unaffected. Verify domains and update templates accordingly to avoid disruptions.
Details:
[Introduction]
To ensure reliable delivery of Teams Events email notifications-and to protect organizations using custom HTML templates-we're enforcing a requirement that all templates reference a verified custom domain in your Microsoft 365 tenant. This improves deliverability, reduces spoofing risk, and aligns with modern email authentication standards. As previously communicated in MC1176301 (October 2025), templates not configured with a verified domain may no longer function as expected after enforcement.
[When this will happen:]
Enforcement was fully rolled out January 31, 2026.
Change Category:
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Scope:
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Release Phase:
Created:
2026-02-19
updated:
2026-02-19
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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linked item details
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summary for non-techies**
Organizations using Microsoft Teams Premium with custom HTML templates for event emails must verify their domain in the Microsoft 365 admin center to ensure successful and secure email delivery, as unverified domains may lead to emails being flagged as spam.
Direct effects for Operations**
Email Deliverability Issues
If custom HTML templates do not reference a verified domain, event emails may not be delivered, leading to missed notifications for users.
- roles: IT Administrator, Event Coordinator
- references: https://learn.microsoft.com/en-us/microsoft-365/admin/email/select-domain-to-use-for-email-from-microsoft-365-products?view=o365-worldwide
Increased Risk of Spoofing
Without verified domains, there is a higher risk of emails being flagged as spoofed, which can damage the organization's reputation and trust with users.
- roles: IT Security Officer, Communications Manager
- references: https://learn.microsoft.com/en-us/microsoft-365/admin/email/select-domain-to-use-for-email-from-microsoft-365-products?view=o365-worldwide
User Experience Degradation
Custom branding and formatting in event emails may fail, leading to a poor user experience and confusion among recipients.
- roles: Marketing Specialist, Event Organizer
- references: https://learn.microsoft.com/en-us/microsoft-365/admin/email/select-domain-to-use-for-email-from-microsoft-365-products?view=o365-worldwide
Configutation Options**
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Opportunities**
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Potentional Risks**
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Data Protection**
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IT Security**
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Hypothetical Work Council Statement**
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DPIA Draft**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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