Symptoms
-
Rouncube shows error:
SMTP Error (250): Authentication failed
-
Checking server externally with telnet is not showing the
AUTH
option at all to theEHLO
command:# telnet 203.0.113.2 25
Trying 203.0.113.2...
Connected to 203.0.113.2.
Escape character is '^]'.
220 203.0.113.2
ESMTP Postfix
EHLO example
250-203.0.113.2
250-PIPELINING
250-SIZE 51200000
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN -
In the
/var/log/plesk-roundcube/errors
the following error may be shown:SMTP Error: Authentication failure: SMTP server does not support authentication (Code: ) in /usr/share/psa-roundcube/program/lib/Roundcube/rcube.php on line 1667 (POST /?_task=mail&_unlock=loading1554712039855&_lang=en_US&_framed=1&_action=send)
Cause
Postfix misconfiguration.
Resolution
-
Connect to the server via SSH;
-
Check that
smtpd_tls_protocols
,smtpd_tls_ciphers
andsmtpd_tls_security_level
,smtpd_sasl_auth_enable
are set as below using the following command:# grep -E "smtpd_tls_protocols|smtpd_tls_security_level|smtpd_tls_ciphers|smtpd_use_tls|smtpd_sasl_auth_enable" /etc/postfix/main.cf
smtpd_use_tls = yes
smtpd_tls_security_level = may
smtpd_tls_ciphers = medium
smtpd_tls_protocols = TLSv1 TLSv1.1 TLSv1.2
smtpd_sasl_auth_enable = yes -
Make sure that
smtpd_tls_exclude_ciphers
,smtpd_sasl_security_options
,smtpd_tls_auth_only
andtls_ssl_option
s are not defined in/etc/postfix/main.cf
file (the output of the command below should be empty):# grep -E "smtpd_tls_exclude_ciphers|smtpd_sasl_security_options|smtpd_tls_auth_only|tls_ssl_options" /etc/postfix/main.cf
-
Reload postfix if any changes were made:
# service postfix reload