Thread 14 SwiftUI - Help to call an API and log in - swift

Question

Hello fellow Swift Coders. I'm a beginner, and i'm trying to call a web API then log in to have access to a new view.
This is my code, everything seems running well (before i try to put the login + pass)
import SwiftUI
import Foundation
struct ContentView: View {
#State private var username = ""
#State private var password = ""
#State private var loginSuccessful = false
var body: some View {
NavigationView {
ZStack {
Color("primaryColor").ignoresSafeArea()
VStack {
HStack(alignment: .top) {
Text("FOLD")
.font(.system(size: 50))
.foregroundColor(Color(.white))
.padding(.bottom, 80)
}
ZStack{
Rectangle()
.frame(width: 345, height: 400)
.cornerRadius(25)
.foregroundColor(Color("secondaryColor"))
.shadow(radius: 10, x: 10, y: 3)
VStack(alignment: .leading) {
Text("Se connecter")
.font(.system(size: 20))
.foregroundColor(.white)
.bold()
.padding(.bottom,50)
VStack(alignment: .leading) {
Text("Email")
.font(.callout)
.bold()
.foregroundColor(.white)
HStack {
TextField("Enter email", text: $username)
.padding()
.font(.system(size: 14))
.foregroundColor(Color("primaryColor"))
.frame(width: 270, height: 50)
.background(.white)
.cornerRadius(10)
}
}
.frame(width: 270, height: 60)
.padding(.bottom, 30)
VStack(alignment: .leading) {
Text("Password")
.font(.callout)
.bold()
.foregroundColor(.white)
HStack {
SecureField("Password", text: $password)
.padding()
.font(.system(size: 14))
.foregroundColor(Color("primaryColor"))
.frame(width: 270, height: 50)
.background(.white)
.cornerRadius(10)
}
}
.frame(width: 270, height: 60)
.padding(.bottom, 50)
Button(action: {
logIn(username: username, password: password)
}) {
Text("Log in")
}
.font(.headline)
.foregroundColor(.white)
.frame(width: 270,height: 40)
.background(Color("buttonColor"))
.cornerRadius(10)
}
.sheet(isPresented: $loginSuccessful) {
QRscan()
}
}
}
Spacer()
}
}
}
func logIn(username: String, password: String) {
let url = URL(string: "https://foldlab.io:8081/loginScanAccount")!
let body = ["username": username, "password": password]
let jsonData = try! JSONSerialization.data(withJSONObject: body)
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = jsonData
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if let error = error {
print(error)
return
}
if let data = data {
let json = try! JSONSerialization.jsonObject(with: data) as! [String: Any]
// Check if the login was successful
if json["status"] as! String == "success" {
DispatchQueue.main.async {
self.loginSuccessful = true
}
} else {
print("Error: Invalid username or password.")
}
}
}
task.resume()
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
}
The thing is, when i'm trying on the simulator or the preview, its crashing. And i have an error i've never seen.
What should i do ?
Thread 14: Fatal error: 'try!' expression unexpectedly raised an error: Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set. around line 1, column 0." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set. around line 1, column 0., NSJSONSerializationErrorIndex=0}
Thanks a lot.
I tried to check on SOF, but i didnt really understand the answers