I'm working from memory, however I believe he should be standing with the head of the fighters guild near the centre of the paths to the three leaders camps (south side) near the stone table with a map. There is a quick conversation and then he heads north into the island and through a door to where he creates a portal to Coldharbour.

I'd run north to the door (through Ayren's camp) and see if you can get through and if not go back to the meeting point and try logging out, exit the game and then run ESO and log your character back in there.