This is a PHP error message that indicates your script is trying to use more memory than the amount specified in the PHP configuration.
A PHP Fatal error is a type of error that occurs when the PHP interpreter encounters a serious problem and is unable to continue executing the script.
This error message typically occurs in PHP when you are trying to access a property of an object or variable that has not been initialized or does not exist.
The require_once function in PHP is used to include a specific PHP file in another file, but it will only include the file once to prevent multiple declarations.