MDErrorReporter/exceptions/generic/MDmainEntityNotExistentException.php

<?PHP
declare(strict_types = 1);

/**
 * Custom exception class for invalid page parameters, which must be values of a
 * preset list of allowed values.
 */
final class MDmainEntityNotExistentException extends Exception {
    /**
     * Error message.
     *
     * @return string
     */
    public function errorMessage() {
        //error message
        return 'Could not connect to databse. Please try again later.';

    }
}