Getting incorrect json format - json

Question

I am trying to print some json connected with urlLink and getting "The data couldn’t be read because it isn’t in the correct format." Below is the code . Not sure what i am doing wrong especially with json serialization:
guard let url = URL(string: "http://localhost/DataDog/registering.php") else {
return
}
var request = URLRequest(url: url)
request.httpMethod = "POST"
let body = "username=\(usernameTxt.text!.lowercased())&password=\(passwordTXT.text!)&email=\(emailTxt.text!)&fullname=\(nameTxt.text!)%20\(surnameTxt.text!)"
request.httpBody = body.data(using: .utf8)
print(body)
print("HPPBODY")
print(request.httpBody!)
URLSession.shared.dataTask(with: request) { data, response, error in
if error == nil {
DispatchQueue.main.async(execute: {
do {
if let json = try JSONSerialization.jsonObject(with: data!, options: []) as? NSMutableDictionary {
if let names = json["id"] as? String {
print(names)
}
}
} catch let error as NSError {
print("Failed to load: \(error.localizedDescription)")
}
})
} else {
print(error!)
}
}.resume()
Json from url is below:
{"status":"200","message":"Succesfully registered","id":"45","username":"adonosisossmahasss","email":"mm#gmsil.com","fullname":"bey mahat","ava":""}

Answer 1

Problem is setting request body
var bodyParam = [String:Any]()
bodyParam["username"] = usernameTxt.text?.lowercased()
bodyParam["password"] = passwordTXT.text
bodyParam["email"] = emailTxt.text
bodyParam["fullname"] = nameTxt.text! + " " + surnameTxt.text
request.httpBody = try! JSONSerialization.data(withJSONObject: params, options: [])