Can't enter Grim Batol

pretty sure you didnt need to do the intro quests prior you could just enter the dungeons.
i think the only exception i can remember is the underwater cata dungeon.

yes, prior.

clearly something with warband messed things up.

not all these people are lying my friend

where did i say they were?

Same thing here - had to get summoned into the dungeon by an alt warlock

We used quest sync triggered by the one who couldnt enter and it worked

If you have someone in a different faction, then you can’t use sync. I am having this issue and it sucks

Had the same issue. Fly east from Dragonmaw Port (starting port) There is a fleet of boats (horde). Fly to the Zeppling on top and you start the quest chain. Just did like 4 or 5, didn’t even open the first town as friendly since couldn’t find the NPC in the port to talk to.
HS to Dormogal, took portal and Dungeon entrance was there.

I have pugged the Vashj dungeon on characters that never went there.
But it wasnt M+

I also seem to remember , after doing the Twilight Highland intro on one character, the portal to Twilight Highlands on the mesa behind the north zep tower in Org, works for all characters.
So, pop in and pop out and see if the queue unlocks.

Sorry I havent the faintest idea where the Alliance cata portals are.