Hi again,
That’s odd…
Have you been creating many, many games… something like the numbers quoted by @TheDarkJedi here ?
If not, then… I don’t know. Perhaps someone else will come up with something that can explain a multi-realm issue like this.
I suppose you could try contacting Blizzard directly with a ticket… there aren’t many support options available to Diablo II LoD but… you could try the ticket form here: https://us.battle.net/support/en/help/contact/354/ticket . You’ll have to explain in details what the issue is but, at least, they’ll be able to look up your account and see if there’s any kind of play restrictions on it.
Good luck with this !