I only have one device(labtop not PC) that connect to my network. Before the disconnect of my internet happen, I will get 90002 from the game, after like some period of time (30-40 seconds), window internet icon the one in bottom right corner will turn from Ethernet connected to a global icon with a circle forbidden sign in the bottom right of the icon. There is no error message pop out. In order to fix this, I need to go to internet and nework under setting in control panel to click repair my internet, once it repair, it will recover. One interesting observation is the amount of time I stay connect to Ethernet is kind of unpredictable, but when I try speed test with xfinity link ->https://speedtest.xfinity.com/ , it will disconnect right way when FFXIV log on. But, if I use dslreports to test my speed, it will not disconnect when FFXIV log on. If I didn't log on FFXIV, everything work find no matter what speed test I use.
Regarding to what I tried, I got the following 3 link from google -> https://www.reddit.com/r/ffxiv/comme...g_my_internet/ and http://forum.square-enix.com/ffxiv/threads/102030, https://www.youtube.com/watch?v=mWRsHEU5T0U, UPnP on my router is checked, and I unchecked "allow the computer to turn off this device to save power" for Broadcom NetLink(TM) Gigabit Ethernet and Broadcom 802.11n Network Adapter in My computer -> property -> device manager -> network adapter, in video it show Realtek PCIe GBE family controller, but I do not have that, so i assume what I did is correct. On one of the post, it mention check window system log, I checked it too, but I do not find things related to internet, I thnk might go the wrong direction, so did not dig deeper