The HTTP 401 code is an authorization error which leads me to believe that your controller is expecting credentials. There is actually a setting in HomeSeer that enables/disables authentication for local connections.
Have you tried adding HomeSeer with your credentials?
If you don’t want to supply your credentials, are you certain you’ve disabled local authentication in HomeSeer?
When MyHS is disabled, the connection is validated by sending a “getdeviceschanged” request. Please open this URL in your web browser & see what it returns. Just replace 192.168.1.203 with your IP address.
Also, “getdeviceschanged” is a fairly new request that HomeSeer added to HS3. It was not in early versions. So please make sure you have all of the latest HS3 updates installed. If you are using HS4 it should already support it.