I just had this problem when trying to do Sastasha. I wound up logging into an alt, which worked. And then I accidentally closed out FFXIV. When I restarted FFXIV, I briefly got 3102, but then I was able to log in.
I suggest shutting down FFXIV and then starting it back up. That's what I'm guessing got me past the 10102 error.
Lyonheart, like Eorzia, will be reborn in FFXIV!
FFXI veteran (Lyonheart and Lakiskline of Lakshmi)
1/467 on signed HQ Weskit!!!