It seems like something like what you’re experiencing happened in the past - July 2020 - and was due to a server migration.
This kind of error is very rare and and don’t know if it’s “fixable” without recreating your account.
I would probably wait for the admin’s answer to this.
Looks like there was a problem creating your account because the index2.html file is missing.
There’s another new post reporting this error in the forums. It looks that there are more users with the same problem.
The admin will probably need to see what’s happening with the process of creating new accounts.
To be honest, I don’t know if you eventually will need to create a new account.
But for now, I would wait for the admin because nothing guarantees that if you create a new account you won’t have the same issue.