ios - Real error message not available with Alamofire -

when using alamofire, don't real error message server sends. instead this:

po debugprint(error.description) error domain=com.alamofire.error code=-6003 "response status code unacceptable: 413" userinfo={statuscode=413, nslocalizedfailurereason=response status code unacceptable: 413} 

how know actual error is, , why doesn't alamofire return actual error message?