How to fix “invalid version” and “could not read Username” in “go get” of a private repository?

You did almost everything right, and only forgot one important step.

You need to tell Go to not check checksums, as you are operating on your own private repositories:

    go env -w GOPRIVATE=github.com/mycompany/*

Replace mycompany with your username on github or the name of your company and go get will most likely work as expected.