ios 关于AFNetworking请求报500

Error Domain=com.alamofire.error.serialization.response Code=-1011 "Request failed: internal server error (500)" UserInfo={NSUnderlyingError=0x7f8608dea390 {Error Domain=com.alamofire.error.serialization.response Code=-1016 "Request failed: unacceptable content-type: text/html" UserInfo={com.alamofire.serialization.response.error.response= { URL: http://120.76.142.118:8080/nursery/api/login/updateheadportrait } { status code: 500, headers

NSString * invoiceId = responseObject[@"data"][@"invoiceId"];
如果是上面这样处理.
阐述一种情况，如上图，请求结果 invoiceid 通过返回的结果我们可以用NSString类型接收，显示也是没有问题，（MJExtension已经处理过）但是如果这个结果需要作为参数传给后台，后台限制类型是字符串，这个时候就会报错500，需要处理的是
NSString * invoiceId = [NSString stringWithFormat:@"%@",responseObject[@"data"][@"invoiceId"]];