Since the beginning of War Within, I haven’t been able to enter Ulduar. I thought it was a TW issue but clearly not. I’ve tried repairing the game but no luck.
Is the character in question a hunter? I know the Haiti questline phases the area and makes it impossible to enter. I believe you need to finish that quest line up and not just abandon it.
Here’s where it starts though I’m unsure where you’re at in the chain.
If it’s not a hunter, what class is your character?