In SO, I saw my duplicate account saying "Unregistered". I don't remember creating it. I tried to merge the account with following link : https://stackoverflow.com/help/edit-logins. But couldn't.

How can I merge / access / delete this duplicate account?

I have looked at a few posts but have found no success:

Can not merge Stack Overflow accounts


What does it mean when someone's an Unregistered User?