TypeError: PhpMyAdmin\Export::getFilenameAndMimetype(): Argument #5 ($filenameTemplate) must be of type string, null given, called in /libraries/classes/Controllers/Export/ExportController.php on line 397 The above error was coming when exporting the MySql with a fresh installation of phpMyAdmin. Solution Go to php.ini and change the max_input_vars to a higher value as the default would be 1000.