Mail is not working on a Plesk server: fatal: no SASL authentication mechanisms

Symptoms

Emails are not being sent from a Plesk server with the following error message in /var/log/maillog :

postfix/smtpd[25002]: warning: SASL: Connect to private/auth failed: Connection refused
postfix/smtpd[25002]: fatal: no SASL authentication mechanisms

Cause

The parameter smtpd_sasl_type is defined in the file /etc/postfix/main.cf:

# grep smtpd_sasl_type /etc/postfix/main.cf
smtpd_sasl_type = ***

By default, Postfix configured by Plesk uses the Cyrus SASL plug-in type.

Resolution

1. Connect to the Plesk server via SSH.

2. Open the file /etc/postfix/main.cf in a text editor. In this example, we are using the vi editor:

   # vi /etc/postfix/main.cf

3. Remove the line with smtpd_sasl_type parameter.

4. Save the changes and close the file.

5. Reload the Postfix service:

   # service postfix reload