Ok boys, I live in mainland China and got it fixed for me.I also had error message 1703. Hopefully it works for you!
Steps:
1: Start up PS5, go to Network.
2: Network settings
3: then again settings
4: Set up internet connection
5: Go to “other” Set up Manually.
6: You get 2 options: “Use WiFi” or “Use a LAN Cable. Choose what is best for you.
7: Go to DNS settings and put it on Manual.
8: Type in Primary DNS 1.1.1.1
Type in Secondary DNS: 1.0.0.1
“Don’t touch the proxy server!!” Leave it on “Don’t use”
9: Press done.
10: Restart the PS5.
Welcome in D4!