I just attempted to make an account on addons.mozilla.org to report a bug for one of the extensions that I use.
When clicking the Register button, or the “I don’t have an account” troubleshooting link, it instead takes me to the login page, showing only “enter you email.” Obviously if I attempt to continue, it simply tells me what I’ve entered isn’t valid, as I do not have an account. I also created a “persona” account, which I am using to post here, but I wasn’t able to log in with that, either.
I have tried this and got the same result in both firefox and chromium; my chromium is specifically for troubleshooting and has no addons or config changes.
I understand what you’re trying to do with this “easy” and unified login/signup flow (you’re copying google), but please just create a simple registration and login page instead. Better yet, entirely abandon the strategy of copying google/chrome.