swift , upload image to php server with alamofire
<p>i upload photo with alamofird with this code :</p>

<pre><code>Alamofire.upload(.POST, Url, multipartFormData: {
            multipartFormData in
            if let Data = UIImagePNGRepresentation(imageData) {
                multipartFormData.appendBodyPart(data: Data, name: "file", fileName: filename+".png", mimeType: "image/png")
                //print(Data)
            }
            multipartFormData.appendBodyPart(data: sessionId.dataUsingEncoding(NSUTF16LittleEndianStringEncoding)!, name: "session_id")
            multipartFormData.appendBodyPart(data: NSUserDefaults.standardUserDefaults().stringForKey("user_id")!.dataUsingEncoding(NSUTF8StringEncoding)!, name: "sender_id")

            }, encodingCompletion: {
                encodingResult in
                switch encodingResult {
                case .Success(let upload, _, _):
                    upload.responseJSON { response in
                        print(response)
                        //var data = JSON(response.result.value!)
                    }
                case .Failure(let encodingError):
                    print(encodingError)
                }
        })
</code></pre>

<p>and i have following Error : <br></p>

<blockquote>
  <p><strong>FAILURE: Error Domain=NSCocoaErrorDomain Code=3840 "Invalid value around character 0." UserInfo={NSDebugDescription=Invalid value around
  character 0.}</strong><br></p>
</blockquote>

<p>and from to day ago this code was working </p>