Unsuccessful user registration for ejabberd server

Client app: iOS Swift iphone

Server: ejabberd

Swift code:

import UIKit
import XMPPFramework

class RegisterViewController: UIViewController, XMPPStreamDelegate {

    var stream:XMPPStream!
    let xmppRosterStorage = XMPPRosterCoreDataStorage()
    var xmppRoster: XMPPRoster!
    
    @IBOutlet weak var userNameTextField: UITextField!
    @IBOutlet weak var passwordTextField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        
        xmppRoster = XMPPRoster(rosterStorage: xmppRosterStorage)
        stream = XMPPStream()
        stream.hostName = "XXXXXXXXX"
        stream.addDelegate(self, delegateQueue: DispatchQueue.main)
        xmppRoster.activate(stream)
        
    }

    @IBAction func registrationBtnClicked(_ sender: Any) {
        
        stream.myJID = XMPPJID(string:userNameTextField.text) //here textField contains user9@localhost
        do {
            try stream.connect(withTimeout: 30)
        }
        catch {
            print("error occured in connecting")
        }

  }
    
    public func xmppStreamDidRegister(_ sender: XMPPStream!){
        print("User registered successfully")
    }
    
    
    public func xmppStream(_ sender: XMPPStream!, didNotRegister error: DDXMLElement!){
        print("User registration failed")
        print(error)
    }
    
    func xmppStreamWillConnect(_ sender: XMPPStream!) {
        print("will connect")
    }
    
    func xmppStreamConnectDidTimeout(_ sender: XMPPStream!) {
        print("timeout:")
    }
    
    func xmppStreamDidConnect(_ sender: XMPPStream!) {
        print("connected")
        
        do {
            try sender.authenticate(withPassword: "pass")
        }
        catch {
            print("catch")
        }
}
    
    func xmppStreamDidAuthenticate(_ sender: XMPPStream!) {
        print("auth done")
        sender.send(XMPPPresence())
    }
    
    
    func xmppStream(_ sender: XMPPStream!, didNotAuthenticate error: DDXMLElement!) {
        print("dint not auth")
        
        if stream.supportsInBandRegistration(){
            stream.myJID = XMPPJID(string:userNameTextField.text)
            do{
                try stream.register(withPassword: "pass")
            }
            catch{
                print("Registration failed")
            }
        }

        
    }
}

Output and Error: