Fatal error: Uncaught Error: Interface "Mailgun\Model\ApiResponse" not found in /home/backend/public_html/fm360/system/vendor/mailgun/mailgun-php/src/Model/Domain/UpdateOpenTrackingResponse.php:19 Stack trace: #0 {main} thrown in /home/backend/public_html/fm360/system/vendor/mailgun/mailgun-php/src/Model/Domain/UpdateOpenTrackingResponse.php on line 19