In a recent confirmed bug Microsoft is describing the cause of the VPN connection failure for many users. The whole statement and proposed temporary solution can be found below. It affects both Windows 10 and 11 operating systems although it is a different update.

Microsoft confirms bug, 

Microsoft confirmed on Thursday that “Certain IPSEC connections might fail” and that they will fix the issue in an upcoming release of Windows.

“After installing KB5009543, IP Security (IPSEC) connections which contain a Vendor ID might fail. VPN connections using Layer 2 Tunneling Protocol (L2TP) or IP security Internet Key Exchange (IPSEC IKE) might also be affected.”

Windows users can remove the KB5009566 and KB5009543 updates using the following commands from an elevated command prompt.

Windows 10: wusa /uninstall /kb:5009543

Windows 11: wusa /uninstall /kb:5009566

Hopefully this will get fixed in a later update.