Hello,
I have the same problem since i reactivated my account on April 14th (and i had it before when i left for a few months).

Sometimes i can stay on for hours, but when 30002 errors start, it can go on for hours.

Not to mention i cannot stay logged in during any raids (still haven't finished Darkhold quest duo to this problem).

I've tried numerous "fixes":
  • Deleting user folder
  • Port forwarding and fixed IP address
  • Leatrix Latency Fix
  • Upgrading router and modem firmware
  • Formatting and reinstalling everything
  • Unplugging router and connecting my PC directly to modem
Of course none of it helped.

I've been told several times "it's your ISP", "it's your router" "...modem" etc...ok I know it's possible, but how come it only affects FFXIV? I can play any other mmo without any problems. I played SWTOR almost 4 months and i dc'd less in 4 months than i dc in one weekened in XIV lol

I'm open for any suggestions and more "fixes" i just don't know what else to do. This one of main reasons i left XIV in November...and I was hoping it would go away, but I guess I'm out of luck.