Unable to connect remotely to MySQL/MariaDB on a Plesk server: Connection refused

Symptoms

• When accessing a MySQL/MariaDB server/database in Plesk from a remote machine, one of the following error messages appears:

  SQLSTATE[HY000] [2002] Connection refused

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  Lost connection to MySQL server at 'reading initial communication packet', system error:61

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  Fatal error: Uncaught mysqli_sql_exception: Connection refused

Cause

MySQL/MariaDB is configured to listen on localhost address only.

Resolution

Configure a remote MySQL/MariaDB access according to this KB article.