Can't use if you downloaded a song using Apple Music – Music Editor: DJ Mixing Studio Review

Good app but I can't use it now that I download song with Apple Music. I can use it on all my tracks I bought before I got my Apple Music subscription. Now that I have Apple Music on my phone any new tracks I download won't work on this app. The app says they aren't downloaded.
Review by Suhveenuh on Music Editor: DJ Mixing Studio.