Apple censored my last reply because apparently listing steps you've taken and commenting on a lack of progress to fix the actual issue makes uncomfortable reading. I have this same problem and have only had an Apple Watch for 4 days. No third party apps run, same as example above, loading with spinner then nothing.
- Tried your suggestion of playing music while uninstalling and installing app, no luck
- Tried the same suggestion of playing music while installing app on a fresh reset watch, no luck
- Tried rebooting both watch and phone several times, no luck
- Tried unpairing and re-pairing watch along with full watch reset, no luck
I've read the suggestion about deleting all music elsewhere but I'm not prepared to do that. I have a 128GB iPhone 6 with 75+GB of music and I'm not going to waste time re-syncing it all to a 4 month old iPhone to get basic features of Apple Watch to work. I've read elsewhere of people who got it working from deleting music, but the problem returned one reboot later or on the next watch app install.
Он избранник богов. - В моих руках копия ключа Цифровой крепости, - послышался голос с американским акцентом. - Не желаете купить. Нуматака чуть не расхохотался во весь голос.