Personal Mp3's once available, now Grayed out

[osu_peanuts]

 I have been purchasing MP'3s for PodCasts and other music that is not available from Spotify. I am a premium user. I know how to add folders. I added my music to my music folder. It showed up. It was available to use. I created a playlist. Two weeks later, in all of my devices it is now grayed out in my local files. I goto that directory. MP3's are there. To trouble shoot. I deleted them, re-added them. No Joy. I created a new folder, added them, no joy. They show up gray. I added more mp3's Gray, no joy. Its hit or miss what now currently grays out and what does not. They are all mp3's purchased from Amazon. This should not be so difficult. These are purchased mp3's the security should not be so harsh that purchased Mp3's from well known artists wont even play. I am excited to see the solution. 
Steps I have taken: Deleted all folders and re-added them 
Re-installed Spotify and re-added songs
Made sure all systems are on same network (shouldnt matter just adding songs but whatever, they are) 
Created new folder on PC, Created new playlist on Spotify, with a new install added songs on all, still Gray for puchased songs on mp3's from Amazon. 
But some songs did work it was hit or miss. So ? What is that?  

[Jemi]

Hey @osu_peanuts, help's here.

It looks like you've done a lot of troubleshooting already, which is great. 

Just one thing, could you try renaming the songs that are not working to something that only includes letters and space, with no special characters or brackets? 

After that, try putting them in another folder to be used as a source and let us know if it helps. Reinstall the app again if necessary 🙂

Thanks!