Itunes on windows refuses to play a song because it isn't authorized

I have authorized the computer. I have logged out and back in. Every time I try to play the song it says it isn't authorized despite me signing in on that specific window to authorize it and it claims it worked. This happened months ago on a different song, but reauthorizing it worked that time. It seems to single outm a song here and there for no apparent reason except to drive you insane. This is happening to one song and that's it. The rest of the 500 songs work just fine. I downloaed it on my phone on the same account. It shows up in itunes as I own the song just like all the other ones, yet it doesn't work. The song plays on my phone, the device I bought it on, but not on itunes for windows or the ipod I try to put it on. What idiot designed this system and what hoops do I have to jump through to play the song that I already paid for? Why does it randomly do this? How do I fix this?