iOS IKEV2 VPN error: why can't I connect via iOS app?

Question

iOS

I created my own VPN server (IKEV2) and I successfully configured and connected through the standard iOS VPN tools.

Screenshot:

I want to connect via iOS app.

Configuration code:

let p = NEVPNProtocolIKEv2()

p.useExtendedAuthentication = true
p.serverAddress = "133.37.212.77"
p.remoteIdentifier = "133.37.212.77"
p.authenticationMethod = .none
KeychainWrapper.standard.set("mypassword", forKey: Configuration.KEYCHAIN_PSK_KEY)
let secret = KeychainWrapper.standard.dataRef(forKey: Configuration.KEYCHAIN_PSK_KEY)
    
p.sharedSecretReference = secret

But nothing happens. What could be the problem? Thank you!