Having similar issues. I've been playing since 1.0 and have had absolutely no connectivity problems from then, right up until a month or so ago. The problem intensified when they disabled the auto d/c function.

My 90002 errors started off as an infrequent annoyance but have recently increased in frequency to a point where i can't play for more than an hour or two without disconnecting.

I've gone into my router settings and forwarded the ports outlined in various guides and they have had little to no effect.

People seem nearly 50 % divided on whether it's an ISP issue or a server side issue with the game but I'm pretty sure(although can't be 100 % certain) that it's not ISP related because surely these problems would have occurred a lot sooner than they have and I play a lot of other games online without problem. The fact I've never had these issues before a month ago with FF XIV leads me to believe it's something that's been implemented server side recently.

Regardless, many many people are having these problems now and the number of people complaining over the past couple of weeks has risen substantially. I really don't want to stop playing FF XIV as i play it nearly daily but with these connection issues, i just can't get myself motivated to do anything worthwhile in game for fear of 90k.