As in the title. The sign up/login page here was stuck for me after clicking the submit button (the circle keeps spinning infinitely). No request blockage from addons as far as I can tell. I unhappily switched to a Chromium based browser and worked instantly. I wonder if others experience the same.
Update: My best guess is that the issue is discussed here, https://github.com/LemmyNet/lemmy/issues/2955
there seems to be a bug if you try to sign-in and that instance already has a user with that username.