iTunes cannot update Apps - Store Temporarily Unavailable

Beginning yesterday, I cannot update many of my apps for iOS in iTunes. If I use Update All it halts updating and says:

Could not purchase 'LinkedIn' (or some other app)

The iTunes Store is temporarily unavailable. Please try again later.

However, if I try to right-click on an individual app some of them will download and update and some give the same error. I've tried rebooting, connecting to a VPN and then trying an update, and I've signed in and out of my AppleID with no effect. It's been this way for more than 24 hours now.