How to fix microsoft teams calendar issue?

Use this troubleshooting path for Teams calendar access issues on desktop and mobile:

1. Verify the Calendar app is enabled for the affected account.
   • In the Microsoft Teams admin center, go to Users > Manage users > select the user > View policies.
   • Open the assigned App setup policy.
   • Confirm the Calendar app with ID ef56c0de-36fc-4ef8-b417-3d82ba9d073c is present.
   • If it is missing, restore it.
2. Verify Teams upgrade mode allows Teams meetings.
   • In the Teams admin center, open Users > Manage users > select the user.
   • Check Coexistence mode.
   • It must not be set to Skype for Business only or Skype for Business with Teams collaboration.
   • If the user is set to Use Org-wide settings, check Org-wide settings > Teams Upgrade and confirm the default coexistence mode is also not one of those values.
3. Verify Teams is not blocked from accessing EWS for the organization.
   • Run:

          Get-OrganizationConfig | Select-Object Ews*
     

   • If EwsApplicationAccessPolicy is EnforceAllowList, make sure these entries are in EwsAllowList:
     • MicrosoftNinja/*
     • *Teams/*
     • SkypeSpaces/*
   • If they are missing, add them:

          Set-OrganizationConfig -EwsApplicationAccessPolicy EnforceAllowList -EwsAllowList @{Add="MicrosoftNinja/*","*Teams/*","SkypeSpaces/*"}
     

   • If EwsEnabled is False, set it to True or Null.
4. Verify Teams is not blocked from accessing EWS for the affected user mailbox.
   • Run:

          Get-CASMailbox <UserPincipalName> | Select-Object Ews*
     

   • If EwsApplicationAccessPolicy is EnforceAllowList, make sure these entries are in EwsAllowList:
     • MicrosoftNinja/*
     • *Teams/*
     • SkypeSpaces/*
   • If they are missing, add them:

          Set-CASMailbox <UserPincipalName> -EwsApplicationAccessPolicy EnforceAllowList -EwsAllowList @{Add="MicrosoftNinja/*","*Teams/*","SkypeSpaces/*"}
     

   • If EwsEnabled is False, set it to True.
5. Run the Teams Calendar App connectivity test.
   • Open the Teams Calendar App connectivity test in the Microsoft Remote Connectivity Analyzer.
   • Sign in with the affected user account.
   • Enter the verification code, accept the terms, and select Perform Test.
   • Review the results for failures or warnings.
   • This test is not available for GCC and GCC High Microsoft 365 Government environments.
6. If the issue is on a Teams Rooms device and the error is Cannot fetch calendar, enable modern authentication on the device.
   • On Teams Rooms, select More (...) > Settings.
   • Enter the device administrator credentials.
   • On the Account tab, turn on Modern Authentication.
   • Select Save and exit.
7. If the environment uses Exchange Server 2019 or 2016 in hybrid mode and the Teams calendar fails randomly, install the required Exchange cumulative update.
   • For Exchange Server 2019, install Cumulative Update 9 or a later cumulative update.
   • For Exchange Server 2016, install Cumulative Update 20 or a later cumulative update.
   • This fixes an Autodiscover v2 site-awareness issue that can cause Teams calendar failures.
8. If the checks above pass, collect the affected user principal name, the UTC time when the issue was reproduced, and Teams client debug logs, then submit a service request to Microsoft Support.

• Resolve interaction issues between Teams and Exchange Server
• Teams Rooms devices can't fetch calendar from Exchange Online
• Microsoft Teams fails to show calendar because Autodiscover v2 isn't site-aware in Exchange Server 2019 and 2016