Songs won’t all sync from Mac to iPhone

I’ve got a new iPhone, and tried to sync my large Music library across from my MacBook (both have latest version of Apple Music, but no subscriptions, all on disk).

Most of the tracks work fine, but quite a few don’t show artwork, and when I try to play them, I get a message “This song is not available in your country or region.”

The thing is, I’m getting this message for albums I ripped myself from the original CD - and even for homemade MP3s recorded by friends, of themselves (i.e, not commercial at all).

I bought my Mac and phone in different regions, but songs I bought through iTunes all seem to work - it’s just this handful of ex-CD music.

Can anyone help?