Fdroid build failed

Hey, i tried to build the seafile app with fdroid build -v -l, but i got an build failed after build successful.
I am using the metadata which is already in the fdroiddata repo, so it should work?

1 actionable task: 1 up-to-date
INFO: Scanning source for common problems…
INFO: Removing gradle-wrapper.jar at gradle/wrapper/gradle-wrapper.jar
INFO: Creating source tarball…
INFO: Running ‘build’ commands in build/com.seafile.seadroid2/app
DEBUG: Directory: build/com.seafile.seadroid2/app
DEBUG: > bash -x -c mvn install -f …/…/srclib/android-vcard/pom.xml -Dmaven.test.skip=true

  • mvn install -f …/…/srclib/android-vcard/pom.xml -Dmaven.test.skip=true
    bash: mvn: Kommando nicht gefunden.
    ERROR: Could not build app com.seafile.seadroid2: Error running build command for com.seafile.seadroid2:2.2.19
    ==== detail begin ====
  • mvn install -f …/…/srclib/android-vcard/pom.xml -Dmaven.test.skip=true
    bash: mvn: Kommando nicht gefunden.
    ==== detail end ====
    INFO: Fertiggestellt
    INFO: 1 Build fehlgeschlagen

Install maven package as the error message says

Do you mean on my local computer?
If yes, i had done it (sudo apt install maven / Debian 10)

But now i got a lot of new errors

I can compile it with Android Studio without problems.

Did you check this (prerequisites)?

Did you try with sudo apt-get install maven instead of apt install?

Maybe also try to get latest versions with sudo apt-get update