Client VPN on Win11 not working anymore after update to 22H2

[MarkK]

Hi, everyone could use some help

All Thinkpads stop connecting to Meraki VPN after update 22H2 on Win11
It works on the previous build and the ones before but not on the 22H2 anymore.

Tried everything from the Meraki site but that does not change anything about the message displayed below.

The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

Tried disabling credential guard as proposed bij MS but that is not the solution.

All the help is greatly appreciated,

Mark

[GIdenJoe]

We only had an issue with an update on W10 last year and that was fixed with a out of band update.

The behavior there was that after receiving MM2 (main mode message 2) from the MX the MS client did simply not continue the IKE exchange.

Maybe you could capture on your WAN side using filter (port 500 or port 4500) or the WAN IP of the client trying the VPN and determine if it is indeed stopping there or if there is another clue like a mismatch in IKE transforms.

[alemabrahao]

It's probably a Microsoft bug. 

[PhilipDAth]

It's not uncommon for Windows update to reset the client VPN settings, breaking client VPN.  Try deleting one of the connections and setting it up from scratch again.