fatal: could not read username for 'https://github.com': terminal prompts disabled

fatal: could not read username for 'https://github.com': terminal prompts disabled

: This isn't a go error, git is returning "terminal prompts disabled". Can you run git clone https://github.com/examplesite/myprivaterepo on your laptop?

I created the private repo examplesite/myprivaterepo using the Github UI from my browser.

Then I went to my go directory (on the desktop) and cloned it:

$ cd $GOPATH

$ go get github.com/examplesite/myprivaterepo

So far so good. Created the file scheduler.go, added to repo, and pushed.

$ vim scheduler.go

$ git add scheduler.go

$ git commit

$ git push

Everythng's OK. But when I went to a clean laptop and tried to clone the repo, I got an error:

# Now on laptop, which doesn't yet know about the repo

$ cd $GOPATH

$ go get github.com/examplesite/myprivaterepo

# At this point it should ask for my user ID and password ,right? But it doesn't.

# Instead, this error occurs:

cd .; git clone https://github.com/examplesite/myprivaterepo /Users/tom/go/src/github.com/examplesite/myprivaterepo

Cloning into '/Users/tom/go/src/github.com/examplesite/myprivaterepo'...

fatal: could not read Username for 'https://github.com': terminal prompts disabled

package github.com/examplesite/myprivaterepo: exit status 128

Why is my laptop hating on my own repo and how can I get it to accept its fate? Thanks.