Some downloaded songs won't play on iPhone

[mtrapanese]

I have a premium account that I exclusively use on my iPhone 7. Regardless of connectivity, certain songs that I have previously downloaded just won't play. I find that they tend to be songs that I downloaded a longer time ago. This was also a problem on my last device, which was an iPhone 6. 

[Maria_B]

Hey @mtrapanese!

Welcome to the Spotify Community.

In this case, are you able to play those songs over WiFi or mobile data? On the other hand, did this start happening after a specific update or event? 

For now, give it a try reinstalling the app and see if you're still experiencing the same issue. Here's how.

Keep us posted.

[mtrapanese]

Reinstalling has fixed the problem, although past experienice suggests this fix will be temporary.

For reference: it does not happen after any specific events and is not impacted by WiFi or offline mode. It's as though a clock starts ticking when I download a song and, after some fairly long period of time, the song becomes unplayable.