I'm not sure if this will work, but click on a song then click on Advanced at the top of iTunes then select 'Create MP3 Version'. I'm guessing you're using songs that were downloaded back when Apple added DRM? I've never had issues with songs downloaded from iTunes then placed onto my Android phone and tablet.
itunes match doesnt remove DRM... all it does is scan your drm free musiccollection and provide you with the same drm music in the cloud.
If you download a matched track to a secondary iTunes library, however, you will get whatever version the iTunes Store has matched it with -- meaning the 256kbps DRM-free version. Similarly, if you were to delete the track from your original iTunes library, you could re-download the "matched" version in 256kbps AAC format.
I've worked with Google tech support repeatedly, to resolve the problem with Music Manager failing to upload most of my music, despite it being in the correct format. they have been unable to resolve it, so far. My music is m4a--music ripped from my own CD's, using itunes. They have received songs from me, in attachments to emails and they THOUGHT they had found the problem, but I still can't load about 1,000 of my songs. I've given up trying to make it work, at this point.
iTunes match does remove the DRM. After iTunes matches all your music in your library all the tracks should have a cloud next to them showing they are now in the cloud. After that, I just deleted the songs on my hard drive library and downloaded the cloud version which is DRM free. Once I did all that Google music manager was able to upload all my iTunes music to the Google cloud.