Songs not playing offline Samsung Galaxy S5

[eminemathers]

As the subject states, my songs are not playing offline. This feature used to work flawlessly but no longer works consistently. I download my libary on Wifi and when I toggle to offline mode, some or all of my songs will not play. Also, the album art does not always show.

Steps I have taken that have NOT fixed the issue:

1. reinstalled the app and erased data/cache

2. checked my microSD card available space (at least 30GB space left)

3. tried Normal, High and Extreme download quality

4. logged in and out of the app

5. restarted my Galaxy S5

I need to get this fixed or I will have to unfortunately unsubscribe as offline mode is a feature I need. Any ideas are greatly appreciated. Thanks.