Errors in /var/log/secure: Unable to connect to Plesk Database: Can’t connect to local MySQL/MariaDB server through socket

Symptoms

• Plesk Obsidian running on a RHEL-based operating system

• In attempt to connect to the server under non-existing user, error below can be found in /var/log/secure file:

  sshd[4568]: Unable to connect to Plesk Database: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (13)

• SELinux is enabled on the server and set to Enforcing mode:

  # getenforce
  Enforcing

Cause

This issues is caused be a known Plesk bug with ID PPPM-10120.

Resolution

The error message can be safely ignored as it does not affect the operation of the database server or the SSH server in any way.

As a workaround, if you wish to get rid of the error, you should apply the steps below:

1. Log into the server via SSH.

2. Disable SELinux by executing the command below:

   # setenforce 0