Apple Music consistently says "You're Offline" while on WiFi

Problem:

My Son's IPAD (base new 2019 iPad, non cellular). On Family Sharing for Apple Music. When opening the app it says "You're Offline" (Turn off Airplane Mode or connect to Wi-Fi). Of course the device is online viewing and downloading etc.

Apple Music works fine on my other 2 kids iPads on Family Sharing on same network using the same exact settings.

I've tried EVERY POSSIBLE troubleshooting including

1. Any forced restart
2. iPad wipe out and reinstallation
3. Network settings reset - also connecting to other WiFi networks
4. Apple Music ON/OFF and any possible modification
5. My son's cloud sign out - sign in
6. Yes, iTunes/AppStore/iCloud use the SAME kid's login credentials

I'm really desperate as there's nothing working.

His library SYNCS, however when clicking on Browse/ForYou/Radio/Search, it says "You're Offline" (Turn off Airplane Mode or connect to Wi-Fi)...of course there is no Airplane Mode turned on and I'm connected to a powerful WiFi network.

(Screenshot below)

So, friends, thank you in advance for any help.

Andreas