Hello Gemma.

Thank you for your purchase.

If you are using separate MySql connection option to connect to mysql database, you can test if connection can actually be established with “Test MySQL settings” button.
If connection can’t be established, first please make sure that all entered values needed for connection are correct.
Also, make sure that MySql server is allowing remote connections and that MySql user that you are trying to connect with is allowed to connect from your sites host (IP address).

If your WordPress is hosted on Azure Web App Services you will need to modify the ../wp-content/plugins/wpdatatables/config/config.inc.php file, around line 65 find this line of code:

$wdtMsSqlDriver = [
'sqlsrv' => ['active' => false],
'dblib' => ['active' => true, 'version' => '7.0'],
'odbc' => ['active' => false, 'driver' => '{ODBC Driver 17 for SQL Server}'],
];

and change it to look like this:

$wdtMsSqlDriver = [
'sqlsrv' => ['active' => true],
'dblib' => ['active' => false, 'version' => '7.0'],
'odbc' => ['active' => false, 'driver' => '{ODBC Driver 17 for SQL Server}'],
];

Let me know if this helps.

Best regards.