A connection stopped working
Why providers drop permissions and how to fix it in a minute.
Email, calendar and messaging providers expire or revoke app permissions: after a password change, a security review, a long period of inactivity, or simply on a schedule. When that happens osmos can't read that account, and you'll see a card asking you to reconnect.
Core → Tool manager → the account → Connect. You'll go through the provider's sign-in again and osmos picks up where it left off. Nothing you've already got is lost.