Greetings Lys_07,
Welcome to Apple Support Communities! We want you to be able to enjoy Apple Music with us on your Roku device. Have you tried restarting the device and then testing again, since it sounds like it's not responding? This simple step can resolve issues like this.
You may also try reaching out to Roku support if the issue continues after the restart:
• Official Roku Support | Roku Device Questions & Troubleshooting
Use these steps to join Apple Music if needed:
• Get the Apple Music app on your smart TV, game console, or streaming device - Apple Support
We hope this helps get Apple Music working normally again.
All the best!