Solved
App Factory Download doesn't exist
Hallo, when I try to export a Task as app and App Factory is not installed, I get a message to download it. But the link is dead:
http://appfactory.dinglisch.net/AppFactory.apk
There is no subdomain appfactory.dinglisch.net obviously anymore. So I ended with download from some apk-download-sites, where I found it. But it doesn't work, which is another bug...
frank
On Tasker 6.1.4-beta (Download version, not Google Play) with Android 9 on Xiaomi Mi A1