First, confirm the connection is still active under Settings → Integrations — Google occasionally revokes access if the account password changes or permissions are edited on Google's side.
If the connection shows Active, try a manual refresh from Reviews → Google Reviews. If reviews still don't appear after that, check whether the review is actually visible on your public Google listing — Google itself sometimes delays publishing new reviews for up to an hour.
If the issue persists past 24 hours, disconnect and reconnect the integration; this forces a full re-authorization and typically resolves stale-token issues.