I was able to get DataHub installed with a lot of effort and I am able to login to the UI using the default credentials. However, it appears that the default user is not authorized to do anything. For example, I tried to create a domain and got an unauthorized error. When I try to view my profile, I also get an unauthorized error. Does anyone have suggestions for how to resolve this?

There should be a view entity page policy enabled in the default list, sounds like that policy was not inside/activated for some reason. Can you login as datahub and insert in some policies? Datahub has platform privileges and should be able to create new policies.