If you’re like me and you have the radio app not working and your Apple Watch is saying: “Sign in to your Apple ID in General in the Apple Watch app on your iPhone” (And of course you are signed in), this solved my issue.
- Go to “Settings -> iTunes & App Store”
- Tap on your logged in Apple ID.
- Tap Sign Out button.
- Reboot your phone (Just in case!)
- Go back to “Settings -> iTunes & App Store”
- Log back in with your Apple ID
- Go to you Apple Watch and most probably you’ll see Radio working! Hurray!
Apple Watch Series 4 just in case. ;)