Okay, so I've been using the local files set up to listen to songs that exist on my MacBook. This hasn't been an issue in the past.

For context, from my Mac I allow Spotify to see local files, I add them to a new playlist, and then on my phone (Pixel 3aXL) I download the playlist for offline use. The other day I attempted to add another file to this playlist using the same aforementioned method, except this time the songs appeared greyed out with an exclamation point to the left where the green download usually appears. 

I found this strange, and decided to delete all of the files and restart. When I attempted to add the original songs back, they were only playable from my Mac. Now, none of the local files are accessible from my phone at all. I'm still using the same file format, same WiFi, and the same method, so I'm not sure what the problem is. 

My Question or Issue

How do I get these files downloaded on my phone so I can listen to them again? Please help, I've tried everything!