Q: trouble downloading from app store

Hi PattiGan,

Welcome to the Apple Support Communities! I'm sorry to hear that you are having these issues downloading iBooks Author. I'm a bit unclear on the exact error you are seeing, but if you are having issues with the iTunes Store or Mac App Store, you may find the information and troubleshooting steps outlined in the following articles helpful:

If you can’t connect to the iTunes Store - Apple Support

Advanced steps for fixing issues with iTunes Store connection - Apple Support

Troubleshooting the Mac App Store - Apple Support

Regards