Having the same issue. I have stormblood on both PC and Ps4. What I found out is that on PC is when I login, I immediately get disconnected with the error 90006. But I can login on Ps4 with no issues. Also, I logged into my friend's account(non-stormblood) on the same computer, and there were no disconnects or lag. So I've ruled out that It's nothing to do with my computer, but Square's servers. Everything was fine the day before.