MainDBException error in Plesk

This article will explain what to do if you get a MainDBException error in Plesk Panel.

Please note: this article was originally created for our previous generation of Virtual Private Servers. As such, these instructions may not be relevant to our current generation of Virtual Private Servers.

The below error normally affects Windows servers, and you should look in the following file to see if port=8306 and is referencing the right file paths:

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PleskMySQLDatamy.ini

Check Windows Firewall is not causing the issue by turning each one (or all) off and try Plesk, check if the Plesk SQL Service service can start/restart via Services.msc. Also check the third tab along to see if Plesk MySQL Server is ticked (under venet0).

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ERROR: PleskMainDBException
No connection could be made because the target machine actively refused it.

0: common_func.php3:619
reconnect()
1: common_func.php3:582
db_connect()
2: auth.php3:146
ERROR: PleskMainDBException
No connection could be made because the target machine actively refused it.

0: common_func.php3:619
reconnect()
1: common_func.php3:582
db_connect()
2: auth.php3:146

If you get:

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ERROR: PleskMainDBException MySQL query failed: Table ‘psa.skins’ doesn’t exist

Check the directive in the my.cnf file on the server lower_case_table_names = 1

The Plesk PSA database uses table names that start with a capital letter. With the above directive set to 1 (enabled) any queries are converted to lower case. As MySQL is case sensitive, this causes Plesk to look for a table called skinsnot Skins. Which causes the failure.

To fix it: Disable the directive in the my.cnf file, restart the server and check the Plesk panel is up and running normally now.