Please check the following....
1) If your target request structure is example MT_Request then your target response structure should be MT_Request_response. Please make sure your response structure from the target side is as explained above.
2) Also in the advanced tab of the receiver channel specify logSQLStatement = true. This will help you to debug the response what you get.
3) Also check whether your receiver channel gives any error for the response. If so, that would be helpful for further proceeding with this issue.
Hope this help.