[sph]

Not sure which is it, but supposing it's a 20+ year old account, it is very likely that:

- the site has been hacked probably dozens of time since I created the account, and my credentials are sold for peanuts these days.

- the password I used wasn't very strong at all, and it has been cracked and shared in plain text for years

- the original domain now probably is in hands of some domain parking bullshit company, selling ads.

In all likelihood, my oldest working account must be the NickServ registration on some IRC network. Though I started with IRCNet and I don't think they had a registration service.

[PopAlongKid]

I've created hundreds of accounts since the mid-1990s. The only two accounts I can think that fall under your description are MySpace and LinkedIn (the latter I joined shortly after it started, and I suppose my MySpace login still works but I haven't tried it in years).

I made a rare (for me) mistake early on, using the same password for Facebook that I was already using on MySpace. Fortunately, I did not use the same email address, so that password was of limited use to anyone else. These passwords have since been changed, of course.