How can i fix "Error Domain=NSCocoaErrorDomain Code=3840 "No value." UserInfo={NSDebugDescription=No value.}"

You need to set the content-type header value to use JSON.

request.addValue("application/json", forHTTPHeaderField: "Content-Type")

Updated the code to Swift 3 and removed everything unrelated to the request:

let myUrl = URL(string: "http://foodhelper.club/registerUser.php");var request = URLRequest(url:myUrl!);request.httpMethod = "POST";request.addValue("application/json", forHTTPHeaderField: "Content-Type")let postString = "userEmail=email&userFirstName=firstname&userLastName=lastname&userPassword=password";request.httpBody = postString.data(using: String.Encoding.utf8);URLSession.shared.dataTask(with: request, completionHandler: { (data:Data?, response:URLResponse?, error:Error?) -> Void in        if error != nil {            print("fail")            return        }        do {            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary            print ("1")            if let parseJSON = json {                let userId = parseJSON["userId"] as? String                print ("2")                if( userId != nil) {                } else {                    let errorMessage = parseJSON["message"] as? String                    print ("3")                }            }        } catch{            print(error)        }}).resume()