Blu-ray players and DVD+R playability?

I took a DVD+R disc on to which I had burned some MP3 tracks into a store and tried to play it in a Blu-ray player. It took more than a minute to “load” and then finally said that it was a data disc that it couldn’t play.

Has anyone had a similar experience with Blu-ray players? I thought these things were supposed to be backwards compatible with DVD players and be able to handle DVD+R discs. Apparently, this isn’t the case.

Not all blu-ray player can play MP3 CDs or MP3 DVDs. Did you check their specs before testing/buying?
Which player did you test?