IIS error: this binding is already being used by a product other than IIS

Error message in IIS

Error message in IIS.

Solution

Port 443 can be assigned to SSTP-service.

Check it by the command

netstat -a -b

Disable the SSTP service

SSTP service

SSTP service.

Stopping related services

Stopping related services.

Now the port 443 is available.