Why is "my templates" so unreliable, it has broken three times since December last year.

Question

"My Templates" is unavailable again, this is the third time in less than six months.

Answer 1

"My Templates" has been unreliable recently because of ongoing service-side issues in Exchange Online and Outlook, not because of anything in the local Outlook configuration.

From December 2025 through at least March 2026, Microsoft has tracked multiple incidents where the My Templates add-in (and sometimes other built-in add-ins like Viva Insights and Salesforce) became unavailable or undiscoverable across Outlook clients:

1. Authentication and backend changes
   • A change to move the My Templates add-in from Exchange Web Services (EWS) to REST authentication caused access errors.
   • Even though that REST change was rolled back, some tenants did not fully recover and continued to see discovery/authentication failures.
2. Service-side discovery regression
   • In affected tenants, the add-in subscription still exists on mailboxes and Centralized Deployment returns it correctly, but Outlook and Exchange services fail to surface the add-in to users.
   • Users cannot see My Templates in the ribbon, All Apps, Add Apps search, or even via Get-App in some cases. This is explicitly described as a service-side discovery or authentication regression, not an admin misconfiguration.
3. Repeated incidents over several months
   • December 2025: Incident EX1183224.
   • March 2026: Incident EX1238375, again impacting My Templates (and sometimes Viva Insights) across Outlook desktop, web, and mobile.
   • March 2026 onward: A broader service incident (MO1243496) where stricter authentication enforcement blocked deployment and user authentication for multiple add-ins, including My Templates, Salesforce, and Viva Insights.

Because these are backend issues, local workarounds (restarting Outlook, re-adding the add-in, etc.) are often ineffective or only temporarily successful. Admin-side actions like re-enabling the add-in with PowerShell (Set-App -Identity a216ceed-7791-4635-a752-5a4ac0a5eb93 -OrganizationApp -Enabled $true) can sometimes help but are not guaranteed to fix the problem while the service incident is active.

In summary, the repeated breakage over the last several months is due to ongoing service-side changes and regressions in how Outlook/Exchange authenticate and discover the My Templates add-in, which have required rollbacks and fixes from engineering and have not always fully remediated all tenants immediately.

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References:

• My Templates are missing from Outlook
• Office Add-ins known issues