For the last month or so my Playstation 4 intermittently gives me the NW-31201-7 error code. This code alludes to cannot connect to the playstation network even though the network is most definitely up and running.
This happens on both a Belkin power lined ethernet connection and the Playstation in-built WiFi connection.
Once I test the connection it will get as far as internet connection test and fail or sometimes get to playstation network sign-in and fail.
As soon as I connect to the 4G hotspot on my Huawei phone it connects with no issues.
I have tried different DNS settings (8.8.8.4/8.8.4.4) and this can sometimes help but it seems like a red herring.