Restart your PlayStation®4 console, connect to the internet using a wired connection if possible, and reconfigure the network settings.
When using a wireless connection, make sure that your PS4® console is as close as possible to your router. Otherwise, remove any items that could be blocking or interfering with the connection.
Turn off your router and modem, wait at least 5 minutes, then restart them.
Contact your internet service provider or network administrator to update the firmware of your router.
If possible, speak to your internet service provider about how to cancel the port filtering function on your router.
Try to manually set up a static IP address by going to Settings > Network > Set Up Internet Connection.