- Plesk for Linux
Note: This article addresses the issue when the Mail Server itself is misconfigured, although the issue might be in Mail Client configuration also, as described in the following article as an example:
Sending a test message in Outlook fails with Plesk mail server: None of the authentication methods supported by this client are supported by your server
Mail server does not return authentication mechanisms list:
# telnet mail.example.com 25
Connected to 203.0.113.2
Escape character is '^]'.
220 mail.example.com ESMTP Postfix
250-AUTH *** <-------------- is absent
Trying to configure mailbox in Android mail client results in the following error:
CONFIG_TEXT: Authentication methods aren't supported by server.
CONFIG_TEXT: Couldn't establish the connection to the server due to untrusted or invalid certificate.
- If trying to send an email using Roundcube an error occurs:
PLESK_INFO: SMTP Error (250): Authentication failed
Postfix is configured to allow SMTP authentication over TLS secure connection, but authentication is not configured correctly.
Note: if the error is shown by RoundCube, refer to the following article first before proceeding further:
Cannot send email from Roundcube: 4.7.1 Relay access denied
- Log into Plesk.
- Check that SMTP authorization is enabled under Tools & Settings > Mail Server Settings > Relay options :
Connect to the server using SSH.
- Run Plesk repair utility:
# plesk repair mail
smtpd_tls_security_levelare set as below using the following command:
# grep -E "smtpd_tls_protocols|smtpd_tls_security_level|smtpd_tls_ciphers|smtpd_use_tls" /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
- Make sure that
tls_ssl_optionsare not defined in
/etc/postfix/main.cffile (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
- Restart postfix service to appy settings from the previous step:
# service postfix restart