Error: “The configuration section ‘system.webServer/management/delegation’ cannot be read because it is missing schema

I had the exact same problem, it turned out I had installed Web Deploy 3.6 on top of 3.5. Remove Web Deploy 3.6 and reinstall 3.5 and see if it solves your issue. You can also try @james-wilkins comment below: “In my case I installed Web Deploy BEFORE installing the management service…”