Ever since the previous updates to the Apple IPhone, i haven't been able to listen to my music when it's not connected to wifi. It's really stupid that I'm not allowed to listen to my music when not connected to wifi. When I had the IPhone 5c, I didn't have that issue. I think you should be able to listen to your music, whether or not its connected to wifi.
iPhone 6s, iOS 9.1
Hello ValerieL20,
It sounds like you have Use Cellular Data turned off for the Music on your iPhone. That could be the reason why it only plays when it is on Wi-Fi.
Go to Settings > Music and ensure that Use Cellular Data and toggle this on. Once you do that, you should be able to play your music without issue. Th reason for this is that the music in your library may not be on your iPhone and in iCloud Music Library. You can also download the tracks to avoid this if you don't want the music app to use cellular data. Check out the articles below for more details.
Music settings
http://help.apple.com/iphone/9/#/iphf2d8534c
Using the new Music app
https://support.apple.com/en-us/HT204951
Take it easy
I can't play music when I'm not connected to wifi, why is that?
