Спасибо всем за ответы и руководство. Моя проблема решена другим способом. Я отправляю строку json в кросс-домен
string = "hi @group1 @group2 *user1 *user2 #fs #ffsd #fsdf";
и сгенерированная строка json
{"raw_msg":"hi @group1 @group2 *user1 *user2 #fs #ffsd #fsdf","msg_type":"group","top_msg_id":0,"file_container":{"file1":{"id":"","file_name":"","uri":""},"file2":{"id":"","file_name":"","uri":""}},***"tag_list":["fs","ffsd","fsdf"]***,"link_list":"","image_container":{"image1":{"id":"","name":"Name","uri":""},"image2":{"id":"","name":"Name","uri":""}},"attached_thread":{"thread1":{"title":"","top_id":"","last_id":""},"thread2":{"title":"","top_id":"","last_id":""}},"to_user":["user1","user2"],"to_group":["group1","group2"]}