itunes match not recognizing computer

You have to delete the protected copies completely and redownload (if they are available - check first before deleting):

Redownload apps, music, movies, TV shows, and books from the iTunes Store, iBooks Store, and App Store - https://support.apple.com/HT201272

Hi,

Firstly make sure that iCloud music library is checked in preferences. Then check the iCloud status of the music in your library on your computer. About iCloud Music Library icons and status - Apple Support

You will be able to checked what tracks have been purchased, matched or uploaded. If the tracks are purchased or matched, you will be able to see if bit rate is less than 256 Kbps. If so, you will need to select the tracks and select remove download. You will now see the download arrow. You can now download the upgraded tracks. Be aware that some previously purchased tracks will be shown as matched instead of purchased. You can still upgrade.

Also you may find that some previously purchased tracks are uploaded. If so, you can burn them to disc then reimport without DRM .

Jim

If they are not in the store at all then strictly speaking you you are stuck with the version you have. Remember though, even DRM protected music can be burned to audio CD and those CDs can be processed like any regular CD, it'll just be in the lesser, original 128k quality. 😉😉