Thank you for the reply,

I apologize for the delay in my response. Disconnects can be caused by a variety of different problems. Performance for FFXIV on your system may drop at higher settings due to network issue or if drivers are not up to date. It could be happening for a number of different reasons. As the game constantly has new content and various things added, it will use new and more recent drivers. Due to that, drivers on computers will need to be kept updated a well.

Also does this issue with the disconnect happen on DirectX 11 or 9?

Hope to see you online!