Exchange ActiveSync TLS 1.3 Certificate Based Authentication Change
Exchange ActiveSync Certificate-Based Authentication now supports TLS 1.3, routing traffic to new tenant-location-based endpoints. Most clients will redirect seamlessly, but organizations using Secure Email Gateways may need to update firewall settings. Rollout began globally, expanding to other clouds by November 2025. As part of our ongoing security efforts, we have made a recent change to Certificate-Based Authentication (CBA) behavior for Exchange ActiveSync. The enhancement is designed to support TLS 1.3, strengthening security and reliability for our customers. With this change all Exchange ActiveSync CBA traffic will be routed to new, dedicated endpoints based on tenant location Specified at MS-ASHTTP: Authorization | Microsoft Learn ActiveSync official documentation, EAS requests without authorization header will be treated as a CBA request. Message ID: MC1169566
The post Exchange ActiveSync TLS 1.3 Certificate Based Authentication Change appeared first on M365 Admin.
Published on:
Learn moreWe can help you with Exchange ActiveSync TLS 1.3 Certificate Based Authentication Change
If you want help implementing, troubleshooting, or improving this product, contact us and we’ll point you in the right direction.
Related posts
OneDrive: Respond to access requests directly in the Share dialog
Review and respond to access requests inside the Share dialog. When people request access to a file, folder, or library, anyone who can share ...
Dynamics 365 Business Central: Expense Agent – Log the expense in a case of lost receipt
Expense Agent helps employees keep expense submissions moving when an original receipt is unavailable. It guides employees through providing t...
Dynamics 365 Business Central: Expense Agent – Set expense spend limits in Expense Management
Take control of employee spending earlier in the expense process with configurable spend limits. Define thresholds that reflect your organizat...
Microsoft Viva: Engage – Improved shared messages end-user experience
Improving the shared conversation experience in Viva Engage to so it’s easier for users to discover, read, and participate. Product Micr...
Dynamics 365 Commerce: Design and print A4 and thermal receipts in a modern designer
Applies to: Point of Sale (Store Commerce app, Store Commerce for web), headquarters (Commerce headquarters receipt format designer), Hardware...
Dynamics 365 Business Central: Expense Agent – Split your expenses
Split a single expense across multiple allocations so costs are accurately assigned to the appropriate expense user, project, department, cust...
Dynamics 365 Customer Insights – Journeys: Marketing tools, skills and plugin are now available in Copilot Cowork
The Customer Insights plugin brings Dynamics 365 Customer Insights context, actions, and guided workflows to Copilot Cowork. Marketers and oth...
Dynamics 365 Business Central: Austria – Enable SAF-T audit file format
This feature extends support for the Standard Audit File for Tax (SAF-T) format to Austria, allowing customers in this coumtry to generate aud...
Dynamics 365 Business Central: France – Install French localization as an extension to the base app
The localized version for France is now available as a set of extensions on the W1 base app. This version includes a data upgrade feature to s...
Dynamics 365 Business Central: Norway – Install Norwegian localization as an extension to the base app
The localized version for Norway is now available as a set of extensions on the W1 base app. This version includes a data upgrade feature to s...