Hi Giorgos, > I am trying to connect my galaxy s9+ via the native IKEv2 client to a > strong swan server of mine via IKEv2-PSK.
That's not exactly what you are doing. From the server's perspective you are using a PSK only to authenticate the client (rightauth), the server is authenticated with a certificate (leftauth, defaults to pubkey and you also load a certificate). Maybe the client expects the server to authenticate with a PSK too, or it doesn't trust the server cert, or the identity doesn't match. Anyway, without client log it's difficult to say what its reason for returning an AUTH_FAILED notify is. Regards, Tobias