Music won't save to offline mode

[fentoozl3r]

I have an iPhone 6 with 6 GB of storage available and when I try to save any music to offline mode, it shows a grey arrow and that's it. Sometimes if I play the song for about a minute and skip to the next one, it will save but only 40-50 songs would do that for me and I have 400 more to save. If I open the app on my computer, there's no problem saving music to offline mode, in fact it only took a minute or two when it was an all-day event to save 50 songs on the iphone app. I've deleted and redownloaded the app three times, checked my subscription status, checked my last payment, turn offline mode on and off, changed sync sensitivity settings from normal to high and then extreme. I know I have not hit my song limit and I know I have enough space on my phone for Spotify to function, so what is the problem?