Start by testing your network connection - if the test shows that your connection is limited, please try the below steps in the order listed:
• Forward ports used by the game
TCP: 80, 443, 3478, 3479, 3480
UDP: 3478, 3479, 3658, 6115, 10000-10099
This step will also help you establish an Open NAT for your connection with the game.
Please note that you may need to forward additional ports for PlayStation Network services.