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Microsoft 365 Sync Problems

PrimeCal connects to Microsoft 365 and Outlook via Microsoft's OAuth flow, syncing events from your Microsoft calendar into PrimeCal. Here's how to fix the most common problems.

Connection Lost or "Not Connected"​

If your Microsoft 365 sync shows as disconnected:

  1. Go to External Sync in PrimeCal (under More on mobile)
  2. Find your Microsoft account in the connected accounts list
  3. Click Reconnect and complete the Microsoft sign-in flow
  4. Accept the requested permissions (Calendar access is required)

Microsoft OAuth tokens can expire, especially if the connection has been idle or if your organization enforces session policies.

Microsoft Work Accounts

If your Microsoft account is a work/school account managed by your organization, your IT admin may have restricted third-party app access. If reconnecting fails immediately with a permission error, check with your IT team whether PrimeCal needs to be approved in your organization's Azure AD settings.

Events Not Showing After Connecting​

If the connection succeeds but no events appear:

Check which calendars are selected for sync:

  • In External Sync, expand your Microsoft account to see the list of calendars available
  • Your primary Outlook calendar, any shared calendars, and secondary calendars (like Birthdays or Holidays) each appear separately
  • Enable the specific calendars you want synced

Wait for the initial sync:

  • After first connecting, the initial import may take a few minutes depending on how many events you have
  • Click Sync Now to force an immediate pull rather than waiting for the scheduled sync

Check the date range:

  • Sync typically imports events within a configured window (e.g., 3 months back, 12 months forward)
  • Very old historical events may not be included

Teams Calendar Not Showing​

Microsoft Teams meetings appear in your Outlook calendar (as "Meetings" calendar entries), not in a separate Teams calendar. If Teams meetings are not syncing, check:

  • Your primary Outlook calendar is enabled in sync settings
  • The event was created in Teams in a way that puts it on your calendar (most meetings do this automatically)

Permission Error During Connection​

If the OAuth flow returns a permission error:

  • Consumer accounts (personal Microsoft/Outlook.com): should have no extra restrictions
  • Work/school accounts: your IT admin may need to grant PrimeCal access in Azure Active Directory. Share the PrimeCal OAuth client information with your IT department if needed
  • Multi-factor authentication: complete the MFA challenge during the connection flow — PrimeCal handles this as part of the standard Microsoft login

Events Stopped Syncing After Working Previously​

If sync was working and then stopped:

  1. Check the connection status in External Sync — look for an error badge on the Microsoft account
  2. Reconnect the account (this refreshes the OAuth token)
  3. If the problem is intermittent, click Sync Now to force a manual refresh

Microsoft tokens can be invalidated by password changes, MFA re-enrollment, or IT policy changes.

Still Stuck?​