12.2 Mailbox connection problems

Symptoms

• Emails from a mailbox stop sending while others continue.
• The mailbox shows a disconnected or error state in Settings → Mailbox.
• You recently changed the mailbox password, or your provider reset app access.

Common causes

1. Password or security change — changing your email password breaks the stored connection. Reconnect.
2. Provider security events — providers (especially Google and Microsoft) revoke access or force re-auth after security changes. Re-authorize.
3. Token expiry — OAuth connections can expire and need re-authorization.
4. IMAP credentials — for IMAP mailboxes, verify server, port, and credentials are still valid.

Fix

1. Go to Settings → Mailbox.
2. Find the affected mailbox and reconnect it, authorizing fresh.
3. Verify the per-mailbox settings survived (signature, opt-out statement, Daily Sending Limit).
4. Send a test email.

Prevention

• After any corporate password policy change, expect to reconnect.
• Check the mailbox list weekly — a silently expired connection means a silently stopped campaign.