xcrun altool returning Package Invalid when notarizing

I have been using xcrun altool command line tools for a year with no problem.

But this week I keep getting a Package Invalid error when I submit my app package to Apple.

I can't think of anything that I have changed on my system.

If I use Xcode to notarize my app, it works.

But command line tools do not work.

I am running Catalina 10.15.3

Any ideas?