sorry to revive this thread again. i'm facing exactly same problem. easiest solution is to restart the router. however the problem came back the next day. having to restart your router everyday before you trying to play ps4 is really annoying. i'm having this issue for 2 months already. and already try new router and still did not fix this problem.

didnt work. already call unifi, they reset port. 2 days after the issue came back. so, one of my friend advice me to change MTU setting in ps4. change from auto to custom, 1480. he said a lot of his friends have this issue and it seems to be working. i am yet to try it. i'll be back and update u if it works.