Unable to enter Theatre of Pain

I’m unable to enter Theatre of Pain on one character because when I approach the entrance I go into a different phase and the dungeon portal disappears. I can only play the dungeon if a warlock directly summons me inside. None of my other characters have this issue. I’ve tried to find an answer on the internet but have drawn a blank and don’t know where to start diagnosing this. I also tried to raise a ticket in-game but the wizard ended in a blank page.

Thanks for any assistance.


Edit: So I found the solution in case anyone comes back to this. I was on a quest chain called “Champion of Pain” (no idea how, I didn’t even have the SL expansion) and needed to complete a few quests starting with “The Arbiter’s Will.”. Thankfully I can now access ToP, though such is a mixed blessing.