Recently, Microsoft has released a portion of cumulative updates as part of the traditional monthly Patch Tuesday for the Windows operating system. As is often the case, the update does not go as smoothly as we would like.
The update appears to prevent the built-in VPN tool from establishing a connection, effectively rendering it useless. Moreover, in addition to Windows VPN, the issue appears to be affecting a number of third-party VPN solutions, including SonicWall, Cisco Meraki, and WatchGuard Firewalls.
Users have already started to complain about this problem on the forums. Microsoft itself has not yet confirmed it.
VPN problems are caused by updates numbered KB5009543 for Windows 10 and KB5009566 for Windows 11. At the moment, the only way to solve the problem is to uninstall these updates.