The PlayStation Network will be down for some maintenance later today. According to a PlayStation tweet, the PSN will receive maintenance from 3 p.m. to 4 p.m. PST.
During that time, users will not be able to sync or compare Trophies. You also won’t be able to view your own Trophy data, so don’t get too concerned if you log on and notice you can’t see your Trophies. This is standard maintenance, so don’t expect any major changes when Trophy service becomes available again.