If you're having trouble with Deliveries for Mac, first make sure you have the latest version from the Mac App Store. OS X Yosemite (10.10) or later is required. You can check your version of OS X by choosing “About this Mac” from your Apple menu. If you're still having problems, consult the list of common questions below! Just click on a question to see the answer.
Updated October 16th: Important: There is a bug in Deliveries 1.0 for Mac that can result in duplicated deliveries if you use iCloud syncing and have the Today widget and app open at the same time. When one these duplicates happen it will also be impossible to archive or delete the one of the deliveries. We're working on a fix, but in the meantime you can avoid the problem by using Junecloud sync.