GoKawiilMicrosoft confirms September Windows 11 updates break Always On VPN
Microsoft has told IT administrators that the September 2026 security updates for Windows 11 versions 26H1, 25H2 and 24H2 can cause Always On VPN connections to fail when automatic protocol selection between IKEv2 and SSTP is enabled. Affected connections may get stuck in a 'Connecting' state or throw a 'port already in use' error on retry. Microsoft has not yet issued a permanent fix but recommends administrators manually set the VPN profile to use only SSTP or only IKEv2 as a workaround.