Fatal error: Uncaught Error: Class 'ProtobufMessage' not found in /var/www/sites/for_new_app/Chat-API-master/src/libaxolotl-php/protocol/pb_proto_WhisperTextProtocol.php:11 Stack trace: #0 /var/www/sites/for_new_app/Chat-API-master/src/libaxolotl-php/protocol/KeyExchangeMessage.php(4): require_once() #1 /var/www/sites/for_new_app/Chat-API-master/src/libaxolotl-php/SessionBuilder.php(8): require_once('/var/www/sites/...') #2 {main} thrown in /var/www/sites/for_new_app/Chat-API-master/src/libaxolotl-php/protocol/pb_proto_WhisperTextProtocol.php on line 11