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OAuth Issues

OAuth is the authorization system PrimeCal uses to connect your Google or Microsoft calendar accounts without handling your password directly. Most OAuth problems have one of a few root causes.

"Something Went Wrong" or Blank Page After Authorization​

If you're sent back to PrimeCal with an error after completing Google or Microsoft sign-in:

  1. Clear your browser cache and cookies for the PrimeCal and Google/Microsoft domains, then try again
  2. Try in a private/incognito window — browser extensions or cached state can interfere with OAuth redirects
  3. Check the URL — if you see error=access_denied in the URL, you declined the permission request during the Google/Microsoft login. Try again and approve all requested permissions

"State Mismatch" Error​

This error means the authorization response from Google or Microsoft doesn't match the request PrimeCal initiated. Common causes:

  • You had the PrimeCal tab open too long before completing the OAuth flow (state tokens expire)
  • Multiple authorization tabs were open simultaneously
  • A browser extension (ad blocker, privacy extension) modified the redirect URL

Fix: Close all PrimeCal tabs, open a fresh one, and start the connection flow from scratch without opening any other PrimeCal tabs during the process.

Google OAuth: "Access Blocked: app has not completed verification"​

This error appears when Google is being cautious about an unfamiliar app. On the warning screen:

  1. Click Advanced
  2. Click Go to PrimeCal (unsafe)
  3. Review the requested permissions and click Allow

This is a standard Google warning for apps that haven't gone through Google's full verification process. PrimeCal only requests the calendar permissions shown.

Microsoft OAuth: "Need Admin Approval"​

If your Microsoft account is managed by an organization (work or school account), your IT admin may need to approve PrimeCal in Azure Active Directory before you can connect.

What to do:

  • Ask your IT admin to review and approve the PrimeCal application in your organization's Azure AD app registrations
  • Once approved at the tenant level, everyone in the organization can connect without individual approval

This is a Microsoft policy for work accounts, not a PrimeCal error.

"Invalid Redirect URI" or "redirect_uri mismatch"​

This error means the OAuth redirect URL doesn't match what's configured in the app registration.

For users of the hosted PrimeCal at app.primecal.eu: this should not occur. If you see it, it may be a temporary configuration issue — try again in a few minutes or contact support.

Token Expired: Sync Stopped Working After a While​

OAuth tokens have expiry limits set by Google and Microsoft. PrimeCal attempts to refresh tokens automatically, but refreshing can fail if:

  • You changed your Google or Microsoft password
  • You revoked PrimeCal access from your Google/Microsoft account settings
  • Your organization's security policies force re-authorization periodically

Fix: Go to External Sync, find the affected account, and click Reconnect to get a fresh token.

Browser Blocking the OAuth Popup​

Some browsers block popups by default. If the OAuth window doesn't open:

  1. Look for a popup-blocked notification in your browser's address bar
  2. Allow popups for app.primecal.eu
  3. Try the connection again

Alternatively, use a different browser (Chrome or Firefox) if your current browser is heavily restricted.

Still Stuck?​