Can't listen to music unless WiFi connected?

This is the first time this has ever happened to me when traveling out of the country. At first I thought it was because the music app changed from iTunes to Music, but I have been out of the country since then. Whenever I travel out of the country, I always have my phone in airplane mode and will connect to hotel WiFi or whatever. I was walking somewhere and went to listen to music that I had previously purchased on my phone and the message popped up "Connect to Wi-Fi or Cellular to Play Music". I tried to play something else that I had synced on to my iPhone that wasn't a purchase, and didn't have any luck. Nothing would play except some podcasts that I had specifically downloaded. I have always, on previous trips, been able to listen to music that has been synced on to my iPhone (6).

I am home now and if I am not connected to WiFi and try to play music I get the message "Connect to Wi-Fi to Play Music". I have never had any issue with playing music and now that it won't let me play my music unless I'm connected is making me frustrated. My audiobooks won't even show up.

Anyone have any suggestions?