What to Do When External Calendar Sync Suddenly Stops

Sync that was working fine and then stops without any changes on your end almost always traces back to something that happened on the external provider's side — not a change you made in your calendar settings.

Check the connection status first

Go to your profile's Calendar Connections and look at the status of the integration. A status showing expired, disconnected, or needing re-authorization tells you immediately where to focus — reconnect it and test again before digging further.

If it still shows connected

1. Check the external provider's own account settings (Google, Outlook, or Apple ID) for a list of connected third-party apps, and confirm access hasn't been revoked there — this can happen automatically during a security review or password change, without you doing anything on the calendar side.
2. Check for a recent password change or two-factor authentication update on the external account — these sometimes silently invalidate existing app connections even when the connection still displays as active.
3. If your team uses a managed Google Workspace or Microsoft 365 account, ask whether an admin recently changed third-party app access policies — organization-level restrictions can cut off a connection that an individual user has no visibility into.

Rule out a simple change first

Confirm the correct calendar is still selected as your linked calendar — if someone recently reconnected the integration and a different calendar got selected by mistake, it will look like sync stopped when it's actually syncing against the wrong destination.

Good to know: Disconnecting and fully reconnecting the integration — rather than trying to repair it in place — resolves the majority of sudden sync failures, since it forces a fresh token and permission grant.