I try to connect to a Windows Server 2019 RAS using L2TP/IPSec with a Pre-Shared Key.
I can establish phase 1 and then the connection gets stuck with an INVALID-ID-INFORMATION error.
The same Router (RB4011 Running 6.47.1) establishes a tunnel using IPSec with certificate to another site using a certificate without problem and I also setup an L2TP/IPSec Server on it which I use to connect to when I am away.
What gets me stuck even further is that I can not connect to the Windows Server with my iPhone too and even though I have logging enabled on the RAS Server there is no log entry.
I do have separate rules enabling UDP 500 and 4500 on the Windows Server.
Where could I start looking for a solution? This error seems to be really rare.