Connection and sign-in problems

What FOLD's connection errors mean, why some of them cannot be overridden, and what you can do.

FOLD only talks to mail servers over verified, encrypted connections. When that is not possible, it stops rather than falling back to something weaker.

Where errors appear

While adding an account: a short message such as IMAP server unreachable; check server, port and encryption. The same message covers unreachable servers, certificate problems and failed encryption.
Later, on the Mac: a bar such as Sync failed: followed by the technical error, for example tlsHandshakeFailed or startTLSNotSupported. The activity log shows the steps before it.
Later, on iPhone and iPad: a short message such as Sync failed.

The certificate is not valid

FOLD checks the server certificate against the certificate authorities your system trusts, and checks that it was issued for the host name you connect to. There is no button to accept an invalid certificate. Anyone who can intercept your connection can present a false certificate; a single click would give them your password and your mail.

What you can do:

Use the exact host name your provider documents. A custom name pointing to the same server usually does not match the certificate.
Check the date and time of your device.
For your own server with a private certificate authority, add that authority to the system and mark it as trusted, or use a certificate from a public authority.

STARTTLS failed

With STARTTLS, the connection starts unencrypted and is upgraded. If the server does not offer the upgrade, the handshake fails, or the server sends data before encryption is in place, FOLD disconnects. Such data can indicate someone interfering with the connection. If your provider offers it, use TLS from the start: port 993 for IMAP, 465 for SMTP.

Unencrypted connections

FOLD has no unencrypted mode. If you choose None as the security setting, the connection is refused. Servers that offer neither TLS nor STARTTLS cannot be used.

Sign-in failed; username or password is incorrect. Check the user name, often your full address. Many providers require an app-specific password when two-factor authentication is on.
Server temporarily locked; too many failed attempts. Wait a few minutes before trying again.
Sign-in declined by the server with a code: the server gave another reason, such as maintenance.

On the Mac, a failed sign-in after setup shows the account name and an Edit button.

The server rejects a message

If the server refuses a message, it stays in the outbox and FOLD tries again. After three failed attempts, the outbox marks it Failed; the Mac reports Sending failed. The message stays in the outbox., iPhone and iPad Send failed. Common reasons are a sender address your account may not use, a rejected recipient, a size limit (FOLD checks the limit the server announces before sending) or a sending quota.

The outbox does not show the server’s reason yet. On the Mac, the activity log contains the SMTP conversation, including the server’s reply code and text.