Stuck with Plesk SASL authentication failure error? We can help you.

As part of our Server Management Services, we assist our customers with several Plesk queries.

Today, let us discuss the symptoms, cause, and fix to this error.

What causes Plesk SASL authentication failure error?

When you attempt to connect with the mail client registers you can see the following errors in the log file /var/log/maillog:

postfix/smtpd[5810]: warning: SASL authentication failure: no secret in database
postfix/smtpd[5810]: warning: example.com[0.0.0.0]: SASL DIGEST-MD5 authentication failed: authentication failure

postfix/smtpd[4288]: Unable to open database(readonly) /plesk/passwd.db: unable to open database file
postfix/smtpd[4288]: warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory

You might be unable to send or receive emails in Postfix after updating to Plesk Obsidian 18.0.34 in Debian 9 OS.

In some cases the Postfix service might be down.

It might cause if the Postfix smtpd.conf configuration file is corrupt.

How to resolve Plesk SASL authentication failure error?

Today, let us see the steps followed by our Support Techs in order to resolve this error.

• Firstly, connect to the server via SSH.
• Then, back up the Postfix configuration file /etc/postfix/master.cf:

# cp -a /etc/postfix/master.cf{,.backup}

• Edit the Postfix configuration file /etc/postfix/master.cf, enable the chroot to the smtp, smtps and submission processes configuration:

From:

smtp inet n – – – – smtpd
smtps inet n – – – – smtpd -o smtpd_tls_wrappermode=yes
submission inet n – – – – smtpd -o smtpd_enforce_tls=yes -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes -o smtpd_client_restrictions=permit_sasl_authenticated,reject -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination

To:

smtp inet n – y – – smtpd
smtps inet n – y – – smtpd -o smtpd_tls_wrappermode=yes
submission inet n – y – – smtpd -o smtpd_enforce_tls=yes -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes -o smtpd_client_restrictions=permit_sasl_authenticated,reject -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject_unauth_destination

• Then, back up the Postfix SASL configuration file /etc/postfix/sasl/smtpd.conf:

# cp -a /etc/postfix/sasl/smtpd.conf{,.backup}

• Next, edit the Postfix SASL configuration file /etc/postfix/sasl/smtpd.conf, configure the saslauthd_path with the relative chrooted path:

From:

pwcheck_method: auxprop saslauthd
auxprop_plugin: plesk
saslauthd_path: /var/spool/postfix/private/plesk_saslauthd
mech_list: CRAM-MD5 PLAIN LOGIN
sql_engine: intentionally disabled
log_level: 4

To:

pwcheck_method: auxprop saslauthd
auxprop_plugin: plesk
saslauthd_path: /private/plesk_saslauthd
mech_list: CRAM-MD5 PLAIN LOGIN
sql_engine: intentionally disabled
log_level: 4

•  Finally, restart Postfix to apply the changes:

# systemctl restart postfix

[Failed to resolve Plesk error? Feel free to contact us at anytime]

Conclusion

In short, today we saw the steps followed by our Support Techs to resolve authentication failure error.