Same thing happened to me on my pro. It said cannot start application. I restarted ffxiv multiple times, restarted my router restored licences nothing worked. I was pretty mad considering early access starts early tomorrow, but what i ended up doing is deleting the game from my pro and just transfering the aplication from a seperate ps4 to my pro took 19 mins for 71 gigs of data and now its working. Thats opposed to 6 hours or more it would have taken had i just redownloaded kt from psn.