Wrong package ID

Hey,
i tried to fork an app and then build it with fdroid, but i got an error after fdroid build
ERROR: Could not build app de.test.forkeddavx: Wrong package ID - build at.bitfire.davdroid but expected de.test.forkeddavx

fdroid lint shows an error too
CRITICAL: No such package: de.test.forkeddavx.yml
CRITICAL: Found invalid appids in arguments

I thought it’s enough to just change the application id in build.gradle, with other apps this works too.
On Android Studio it works too

This is my metadata file
https://privatebin.net/?6e1f153329ecda82#Hif5f4hbqEeNVRUB5BnXwrdriDPhAcNXFPb6t9511VEP

Well it depends on the app code…

ok, can you give me some advice on where to look?

This is the app code:

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