Postfix SASL ERROR: Password not accepted from server: 535 5.7.0 Error: authentication failed: authentication failure

Q. I've recently changed email user account password using passwd command, for one my postfix email server which requires SMTP authentication before sending an email. Now following error is logged into my /var/log/maillog file:

ERROR: Password not accepted from server: 535 5.7.0 Error: authentication failed: authentication failure

How do I solve this problem under Red Hat enterprise Linux running Postfix with SASL authentication?

A. It appears that you are using Simple Authentication and Security Layer (SASL) framework for authentication and data security in Internet protocols. Cyrus SASL is a free and portable SASL library and it is used for SMTP authentication.

To set or change a user's sasl password use saslpasswd2 command and not passwd command. saslpasswd2 is used by a server administrator to set a user’s sasl password for server programs and SASL mechanisms which use the standard libsasl database of user secrets. Type the following command at shell prompt:

# saslpasswd2 username

Now password should be updated and Postfix should accept the SMTP password.

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