VPN server not working, RemoteAccess event 20063

Today I experienced another issue with Windows 10 upgrade (to the Fall Creators Update) and the VPN server functionality. After quick research, it turned out that errors are written to the event log after each client's attempt to connect:

• Remote Access Connection Manager failed to start because the Protocol engine [rasgreeng.dll] failed to initialize. The specified module could not be found.
• Remote Access Connection Manager failed to start because the Protocol engine [IKEv2] failed to initialize. The request is not supported.

Looking for mentioned .dll led to dead end - no such .dll exists on any my Windows 10 machines. However, then I checked the services and noticed that one of them related to remote access - Remote Access Auto Connection Manager (RasAuto) is not running. So I changed the startup type option from Manual to Automatic, restarted PC, and everything worked like a charm.