Cannot play song in iTunes – told I'm not authorized but I am

I'm on a Late 2008 Aluminum Unibody Macbook

Using iTunes 12.1.0.50

When I try to play a certain song, which I happen to have purchased on an old iPhone, or a certain album that I got through Family Sharing with my husband, I am prompted to authorize the device:

I enter my details and then I get this:

But no luck, the songs won't play. I get the first prompt again:

Note that this only happens with two songs purchased on my old iPhone (by Jamie Woon), but not any others, and one album (Yellow House by Grizzly Bear) obtained through Family Sharing.

Please help