I have already submitted 2 tickets to the support and got the same answer both times, which had nothing to do with my case.
I bought the game and the dlc's a few days ago on Steam and installed everything. I booted the game up, chose to make an account in-game, got the activation email, and was able to login to the ESO website. I returned to the game, input my credentials, and it gave me an error "Unexpected Internal Error". I exited out of that window and clicked 'login' again, this time the "Requesting Login" window popped up and stayed there for 40-45 minutes before I force quit.
I went back to the website, unlinked my steam account and tried logging in again. Got the same error and infite requesting login window. I tried the "repair" option from the launcher twice, checked to see if it was my anti-virus, tried a different mega-server. Nothing fixed the issue.
I asked a friend to login to their steam account through my PC, and try launching the game and logging in. The game worked, no error message. We logged in to my Steam account from their PC and got the error message and infite login window.
Steam doesn't have technical support for ESO, and the official support is telling me to contact my ISP (so a bot is responding automatically without even looking at what my issue is).
It seems obvious that the issue is with my account, but the game won't let me link a new account even if I unlink through the ESO account options on the website. I can't find a solution on the forums either, though I doubt this is something I can fix. Is this happening to anyone else?