Photon PUN 2: ConnectUsingSettings() failed

The error message is: „ConnectUsingSettings() failed. Can only connect while in state ‘Disconnected’. Current state: Connected“ What do I Have to do?

if (!PhotonNetwork.IsConnected)
{
PhotonNetwork.ConnectUsingSettings();
}
else
{
// Remember you do not need to disconnect and connect again, you can join lobbies and create rooms
PhotonNetwork.Disconnect();
}

And on disconnected, Connect again:

public override void OnDisconnected(DisconnectCause cause)
    {
    }