Unable to log in to Roundcube/Horde webmail in Plesk: ssl_cert: Can't open file

Kuzma Ivanov

Updated January 13, 2026 19:07

Plesk for Linux kb: technical ABT: Group A

Applicable to:

When logging in to Roundcube/Horde webmail, the login fails with:

PLESK_INFO: Connection to storage server failed.

or the page loads for some time and then shows:

PLESK_INFO: Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
The Dovecot service fails to start. The following error message appears in /var/log/maillog or in the service status:

CONFIG_TEXT: dovecot: config: Fatal: Error in configuration file /etc/dovecot/conf.d/14-plesk-sni-example.com.conf line 7: ssl_cert: Can't open file /usr/local/psa/var/certificates/scfNkZxBn: No such file or directory

The SSL certificate file for securing domain's mail does not exist in the system.

Connect to the Plesk server via SSH.
Check if the domain from the error message exist in Plesk with the command:

# plesk bin site --list | grep example.com

If the domain exist

If the service still fails to start, apply the following steps:

Log in to Plesk.
Go to Domains > example.com > Mail Settings.
Set the option SSL/TLS certificate for mail to "Not selected" and apply the changes.
Select SSL certificate back and apply the changes.

If the domain does not exist