MDMailer/exceptions/MDMailerEncryptionFailedException.php

<?PHP
declare(strict_types = 1);

/**
 * Exception to be thrown
 */
final class MDMailerEncryptionFailedException extends Exception {
    /**
     * Error message.
     *
     * @return string
     */
    public function errorMessage() {
        //error message
        return 'GPG encryption failed';

    }
}