Ok I am not sure what is wrong, here is what I would try to see if maybe they are issues:
– check that the PART VOCALS track actually has the correct name in midi also as text event
– add also a VENUE track just in case
– add another PART <instrument> track and see if it makes any difference
DRYVOX is not a midi track by the way, it’s an audio track, but I assume you didn’t mean it’s in the midi because it’s just not possible.
Then again, if you’re not already using C3 template to create the tracks, you should do so: start a new project with C3 template and copy your vocals chart into the pre-generated PART VOCALS track. The C3 template gives you correctly formatted “blank” midi tracks, so it should have all the basic required events to make the exported midi compiled by Magma.