The 'Call to undefined function mysqli_connect() in ... ' error

This problem can be caused by that MySQL has been updated on the server where your CS-Cart is installed. The MySQL version is defined during the CS-Cart installation and it is not redefined automatically for CS-Cart after MySQL update.

To redefine the MySQL version:

1. Open the config.php file located in the root CS-Cart directory.
2. Find the following line of the code there:
   

   $db_type = 'mysql41';

   
   and replace it with this one:
   

   $db_type = 'mysql';

3. Save the file.