The Apple Music authentication made by Apple could have some difficulties to load time to time (nothing we can do on our side for that unfortunately). If you got any issue with it, we recommend you to temporary disabled your browser extension. If still not working give a try with another browser / device or network.
Be aware "child" Apple account are not allowed to use the "Apple Music API" and so, the authentication process will failed.
The authentication process to connect an Apple Music account inside the Soundiiz Android App could also fail. In that case, we recommend you to use Google Chrome browser directly instead on your Android device and go to https://soundiiz.com/webapp to connect Apple Music to your Soundiiz account from there.