My email account keeps disconnecting itself — what now?

OAuth tokens can expire or be revoked. Common causes:

1. Password changed at Gmail / Outlook — refresh the connection under Email → Accounts → Reconnect
2. Too long inactive — some providers revoke tokens after 6 months without use
3. Security check at Google: in your Google account → Security → Connected apps → check whether Senly is still in the list
4. IMAP settings changed — check host/port/SSL

Reconnect: Email → Accounts → Add account with the same mailbox. Existing threads and history are preserved.