For months i've had problems with 90K error that would swiftly kick me to 2002. That among tons of lag spikes. It made the game simply unplayble. I felt like i wasted money. Which technically i did. because i paid for 6 month and was unable to play for 5 of them. I stumbled across this solution by complete mistake. Now this MAY not fix the problem for everyone but this fixed all my issues with FF14 90K's and overall PS4 Internet connectivity. Below is the video that walked me through step by step and when i was done, i had no more spikes, i had no more lag, i had no more 90K/2002 save for the current DDOS attacks. But beyond that i've been playing with not a single problem. I've watched people not really try to help others that suffer from this problem. Simply because it doesn't affect them. So now that i got my problem fixed I hope it works for you guys as well

http://youtu.be/NPRyHw6fWqY

Good luck everyone

P.S. Again this may not work for you but it worked for me.