Hi Andrew,
The authorization callback URL will return a 404 if you try to access it without providing a valid code in the URL parameter. If GitHub is showing that a user is connected, I think that means that the authorization callback process succeeded.
The
GitHub integration feature is only used on the Playground -> Packages screen. It provides a "GitHub" button that is used to push a docassemble extension package to GitHub.
Installing a package from GitHub does not require GitHub integration to be set up. You should be able to go to Package Management -> Update a package and enter the URL of an existing public GitHub repository. There is also a "Pull" button under Playground -> Packages that does a similar thing.
I am curious to know more about how exactly you got to the screen with the error that said "There was an error updating packages." Also, there might be some information in the "Logs" about what went wrong.