A mailbox shows an error

When Heron can no longer reach one of your mailboxes, a banner appears at the top of the message list and you get a notification. Your other mailboxes keep working normally.

The “Fix” button

Click Fix in the banner: Heron opens that mailbox’s settings, with an explanation and what to do. On mobile, tap Fix in the list’s banner.

“Sign-in failed for …”

The mail server rejected the username or password. Most often the password changed, or an app password was revoked.

1. Click Fix.
2. Under Server & Connection, enter the new password (for iCloud, Yahoo or Fastmail, create a new app password).
3. Click Save (on mobile: Save connection). Heron checks the connection before saving.

“Authorization expired: reconnect the account”

For a mailbox connected with Google or Microsoft, the access you gave Heron expired or was revoked (for example after a password change, or from your account’s security page). Click Fix, then Sign in again with Google or Sign in again with Microsoft, and finish signing in in your browser. Syncing resumes right away.

“Cannot connect to …”

The server isn’t responding. This can be:

• a temporary outage at your provider: wait a few minutes, then click Try Again Now;
• wrong server settings (address, port, SSL) for an IMAP mailbox: check them under Server & Connection against your provider’s information;
• too many open connections, especially with Gmail: see Gmail: too many connections.

Still stuck?

• Remove the mailbox and add it again: see Add a mailbox. Your emails stay on the server.
• For a work Microsoft 365 account, check with your administrator that Heron is allowed and that authenticated SMTP sending is enabled.
• Otherwise, contact support with the exact error text.