First time login with github fails

I thought I’d try tailscale for the first time today.
I went through the first steps to use my github account on Windows 10 to add my first computer.
Everything went smoothly at first, l downloaded and installed the tailscale app, even got the email from github saying that OAuth access by tailscale had worked.
However, my first try clicking the tailscale icon to login brings up a browser tab in firefox asking me for an email.
However, the tailscale instructions said to use ‘mygithubuserid@github’ but this just returned the login page again and again asking for an email. (I used what the tailscale web page told me to use to login, i.e. my actual github userid)
I tried my github email address, too, but that also did not work.
And now, it’s simply saying “Sorry, we can’t log you in”
Too bad, I guess I’ll have to give up on using tailscale, it really sounded useful.