ERR Plaintext authentication disallowed on non-secure (SSL/TLS) connections

Posted in March 2012 by under sysadmin

If you get the error

"ERR Plaintext authentication disallowed on non-secure (SSL/TLS) connections"
            

You need to check a couple of settings in your Dovecot configuration.

1. First check in /etc/dovecot/conf.d/10-auth.conf and make sure that

disable_plaintext_auth = no
            

2. You also need to make sure in /etc/dovecot/conf.d/10-ssl.conf that

ssl = yes
            

and NOT

ssl = required
            

Remember to restart dovecot after making the configuration changes.

service dovecot restart