Good morning! Thank you for posting in the Final Fantasy XIV Technical Support Forums.

We apologize for any inconvenience experienced when trying to play Final Fantasy XIV.

Just to confirm, are the cookies and cache cleared from the PlayStation 4 Web Browser? Are Final Fantasy XIV and the PlayStation 4 fully updated? Have you attempted to power cycle the router(s)/modem(s)? (Unplugging the device and leaving it idle for 10-15 minutes) Are there any others on the network when playing Final Fantasy XIV?

So we may further assist and gather more information, please provide the following:

Does the disconnection/lag happen to one character or multiple characters?
Where in game do you get disconnected/experience the issue?
What ISP Is being used?
Error messages received?:
Wired or WIFI connection?

Thank you once again for visiting the Final Fantasy XIV Technical Support Forums!