I've been using the Stack Exchange Android app to ask and answer questions since I got my new mobile phone. The app created a profile for me named "user2021", as you can see. I have no idea how to log into this account through the main SE website in order to change my screen name.
The SE login screen doesn't recognise either of my two email addresses when I try the "reset password" link, nor do trying the Google or Facebook login routes work - Google gives me "this is a new account", and FB logs me in under my FB name and with my user2021 posts appearing like any third-party posts.
How do I log into my user2021 account through the main website, when i don't have any email address, google account or facebook account associated with it??