Keep having them try. When I first started on Cactuar, there was a lock down in place and I kept trying until I got in so that I could play with a friend.

When I had my friend join us, they had the same issue and couldn't get in for hours. XD If you want it enough, it'll happen and it's better than the alternative where there's no one to play with at all.

I came from XI where the server was a dead wonderland of emptiness.