Thank you for using Apple Support Communities.
I see that you are having an issue with not being able to download music from your Apple Music account. I would first suggest that you review the following support article that covers downloading content from Apple Music to make certain you aren't missing anything.
Add and download music, shows, and movies from the Apple Music catalog
If, after checking this article you are still having issues, there are a few additional questions that could help us narrow down what might be going on.
1. Have you ever been able to download content from Apple Music?
2. Anything changed prior to the issue occurring? Software reinstallation or update, etc?
3. Have you verified that you are using the correct Apple ID for the Apple Music subscription concerned?