Microsoft has resolved a known issue that caused Always On VPN connection issues after installing the September 2026 Windows 11 security updates. [...]
Microsoft fixed a failure in Windows 11 Always On VPN due to September 2026 updates. The problem prevented VPN connections and connections, displaying the ☆ errorThe specified port is already in use. Updates KB5127648 and KB5127646 fix the failure, while the temporary alternative is to configure the profile to use only the SSTP or IKEv2 protocol, depending on the tunnel type and infrastructure.