Fatal error: Uncaught TypeError: MessageBird\RequestValidator::validateSignature(): Argument #1 ($signature) must be of type string, null given, called in /home/apikharedi/public_html/api/vendor/messagebird/php-rest-api/src/MessageBird/RequestValidator.php on line 194 and defined in /home/apikharedi/public_html/api/vendor/messagebird/php-rest-api/src/MessageBird/RequestValidator.php:133 Stack trace: #0 /home/apikharedi/public_html/api/vendor/messagebird/php-rest-api/src/MessageBird/RequestValidator.php(194): MessageBird\RequestValidator->validateSignature(NULL, 'https://api.kha...', '') #1 /home/apikharedi/public_html/api/vendor/messagebird/php-rest-api/examples/signed-request-validation.php(10): MessageBird\RequestValidator->validateRequestFromGlobals() #2 {main} thrown in /home/apikharedi/public_html/api/vendor/messagebird/php-rest-api/src/MessageBird/RequestValidator.php on line 133