Do you know what IP/Server your game is connects to? May help the support team troubleshoot.

While playing the game and logged in, alt-Tab to go back to Windows, press Windows-R to run a command, type in 'resmon' and hit 'Enter' to start Windows Resource Monitor. Under the Network bar look for ffxiv_dx11.exe process, and the FFXIV server your computer is connected to is listed under 'Address'. It can also be found under 'TCP Connections' and 'Remote Address' column.