Fix "This computer is not authorized" after importing itunes to Sonoma

Just migrated (manually) from High Sierra to Sonoma, and after opening Apple Music for the first time I went and selected where my iTunes library was saved on a non-system drive. Apple Music appeared to import the library but anytime I go to play music I created (i.e. didn't download, but made on my own computer and then imported) it says "This computer is not authorized." and doesn't play.

When I play downloaded music it says the same thing, but then it starts playing.

There is over 15 years of similar threads about the same error across many now irrelevant OSes, so searching through this forum has been difficult. Hoping someone has specific tips on importing from High Sierra to Sonoma.

Thanks!