Within the panel on the left, scroll to the Contacts application and select it. Within the apps panel on the right, scroll to Postbox and make sure that it is selected.

What is postbox on Mac?

Postbox is a desktop email client, news client and feed reader for Windows and macOS. ... Postbox was founded and staffed by several former developers from Mozilla. The software was built using Mozilla's Gecko browser engine, and was initially based on Thunderbird, Mozilla's own e-mail software.

Is there a postbox app?

What is Postbox? Postbox is the power email app that helps you work faster, save time, and get more done.