Theme error on installation

I installed the latest version from

The front end works perfectly fine.

But I could not access admin and I get the following message

The Pressbooks Book theme is not installed, but Pressbooks needs it in order to function properly. Please visit GitHub for installation instructions.

It works for me

Is better if you have two installations, one for testing and other for production. So you can fix issues before to use the updates in the production site.

Do you use the default PB theme?

Thanks…it works now…I have re-installed the latest theme and the problem fixed