Why won't the songs I purchase from Google play actually play without wifi? I have set the settings to download without wifi. I don't care about the data. I don't like waiting until I get home to be able to finally put the music I have purchased on my phone
Stumbled across this thread since I am having a similar issue with my unlimited google music subscription; hope your issue has been resolved by now!
I had this issue happen randomly to me. I was able to stream all the songs in my library, then suddenly half of them were grayed out and wouldn't play ("Can't play this song without internet connection").
I contacted Google customer support and they helped me fix the issue. They said that my phone hadn't checked in with their servers in 24 hours, so they had me force my phone to do that. They had me change the date, time, and time zone in the Date and Time settings. They recommended to change it so there were no similarities (i.e. if its AM there, choose a time in the PM; if its 2015 change it to a date in 2016; etc). I verified the time and date changes on the home screen, then changed the Date and Time settings back to Automatic.
They then had me fully close the music app and reopen it, and voila, all my songs would play via cellular data again.
I noticed I was having this issue when I went camping, only to find about 30% of songs I downloaded weren't available. A screenshot of this is shown below.
Even removing and re-downloading an album wouldn't fix the problem. Changing the clock as Austin suggested didn't help either.
While connected to wifi (disable download only mode), go to Settings > Account > Refresh. Wait a few moments. Play a different song, then start playing your album again. This fixed the issue for me, and I really wasn't expecting it to be so easy.
And you can test this by using Download Only mode in the main menu.
Below is what it looks like when some songs you downloaded don't work offline (or in download only mode).