So I had something similar happen to me. I started out at the _ sign in _ page, I attempted to sign in with google, it remarked that I don't have an account and sent me to the _ sign up _ page that looked very similar to the sign in page, and from there, I was able to create an account via my google account.
1. https://chat.zulip.org/register/
2. "Sign up with GitHub"
3. "Authorize zulip"
4. Got redirected to "Sign up for Zulip" (https://chat.zulip.org/complete/github/?redirect_state=...)
5. Went to https://chat.zulip.org/ and
6. got redirected to https://chat.zulip.org/login/
7. "Login with GitHub"
8. "Zulip account not found."
Can you open an issue on http://github.com/zulip/zulip/issues/new? We haven't heard similar reports in the year since the GitHub auth backend was added, so I'm guessing there's something special about your account (or maybe a problematic browser extension); I'd love to debug this with you.
