"535 5.7.8 Error: authentication failed: authentication failure" with postfix and dovecot sasl authentication
Solution 1:
OK, I was able to get authentication working by adding the following lines to the postfix main.cf config file:
smtpd_sasl_path = private/auth
smtpd_sasl_type = dovecot
smtpd_sasl_auth_enable = yes