KB5009543 or Cumulative update Jan 2022 for Windows 10 and Windows 11 is currently breaking IKEv2 VPN connections. If you are experiencing an unexpected connection failure with a vague error message like “General processing error”, please follow the below steps.

Go to Program and Features -> Installed Updates and uninstall KB5009543. Reboot the box and the VPN connection should start working normally. Optionally you may disable the Windows Update for a period of time so that the same update will not get installed once again. Please note, Microsoft releases updates to their products quite often to resolve issues those were identified. Few times these updates open new issues, like the one happened with this particular KB.

While there are no straight forward methods available to “stop” Windows updates, you can use multiple methods to disable Windows update completely, which we don’t recommend. One of them is using group policies on the local machine.

If you still consider disabling Windows updates temporarily/long term, please refer this excellent tutorial

Hope this helps.