URL: https://my.account.sony.com/sonyacct/signin/?duid=000000070009010026e09e231d7729aaf86ea63d96b1e5189a33cb0903fd703d9a50316d7886fc80&response_type=code&client_id=e4a62faf-4b87-4fea-8565-caaabb3ac918&scope=web%3Acore&access_type=offline&state=042fe9a4de7403451d856220681a4566f3339f3dbab45cee46128a11233b459f&service_entity=urn%3Aservice-entity%3Apsn&ui=pr&smcid=web%3Apdc&redirect_uri=https%3A%2F%2Fweb.np.playstation.com%2Fapi%2Fsession%2Fv1%2Fsession%3Fredirect_uri%3Dhttps%253A%252F%252Fio.playstation.com%252Fcentral%252Fauth%252Flogin%253Flocale%253Den_GB%2526postSignInURL%253Dhttps%25253A%25252F%25252Fwww.playstation.com%25252Fen-gb%25252F%2526cancelURL%253Dhttps%25253A%25252F%25252Fwww.playstation.com%25252Fen-gb%25252F%26x-psn-app-ver%3D%2540sie-ppr-web-session%252Fsession%252Fv5.32.1&auth_ver=v3&error=login_required&error_code=4165&error_description=User+is+not+authenticated&no_captcha=false&cid=06d0b353-655f-4544-9273-380a09d89aac#/signin/input/id

Browser / Version: Firefox 119.0
Operating System: Windows 10
Tested Another Browser: Yes Opera

Problem type: Something else
Description: After writing a valid email address and pressing 'Next', no other pages are able to be loaded in other tabs and RAM usage spikes.
Steps to Reproduce:

1. I wrote in a valid email addres on the sony account sign-in.

2. I pressed 'Next'.

3. The browser is unable to load any other pages from other tabs and begins to slow down, has to be restarted.

(tested in Opera and it works, so it's Firefox specific and has multiple threads on the internet confirming this issue in Nov 2023 as I'm reporting this.)

View the screenshot

From webcompat.com with ❤️