The old Projector 2019 apps have now been deprecated. They will no longer be able to login to Planning Center Services, which is necessary for the app to function.
If you are still running the old app, simply update the app in the Apple App Store, and you will be running the Projector 2020 app version, which is fully supported.
The Projector 2020 apps also have a built-in ‘update reminder’ feature, to help make sure that you never get caught running an old, unsupported app version going forward, since Projector will ‘bug’ you every time it starts up if the app is out-of-date.