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 to start Windows Resource Monitor. Under the Network bar look for ffxiv_dx11.exe, and the server your computer is connected to is listed under 'address'. It is also seen under 'TCP Connections' and Remote Address.