The first check you need to do is to see if we get a response from the server at all. There can be many reasons why you didn't get a response from the server:
Use the IsSuccessfulRequest property (of the Response object) to check if your request went through OK.
Use the ErrorCode and ErrorMessage properties (of the Response object) to get an indication of the error.
Define_Com Class(#XPRIM_HttpRequest) Name(#Request)
...
#OK := #Request.Response.IsSuccessfulRequest
#ErrorMessage := #Request.Response.ErrorMessage
#ErrorCode := #Request.Response.ErrorCode
Note that Response.ErrorCode and Response.ErrorMessage indicates an error that occurs on the HTTP/network layer. If your error occurs on the application level (for example, the authorization token you passed is not valid), the error won't be reflected in the Response.ErrorCode/Response.ErrorMessage.