We use Apple’s TestFlight system to deliver our app to customers (https://en.wikipedia.org/wiki/TestFlight) it’s like the private App Store. Unfortunately Apple’s system requires that app installs “expire” after 60 days, but all you have to do is update or re-install our app to reset that 60 day clock. Install the TestFlight app and open it (you may already have it installed). You should see an entry for “Canviz” and you should see a button that says “install” or “update”. Tap that button.
We will be releasing our app, publicly, to the App Store very soon so you shouldn’t have to deal with this TestFlight issue again (you’ll install using the App Store).