Error Dialog: Error while "Speichere" (saving)

Hi,
when trying to overwrite an existing file xxxx.kdbx on my Debian server via WebDav, I received this error message (just fyi):

title: Error while Speichere
content: StorageException{type: StorageExceptionType.conflict, details: Precondition failed., errorBody: null}
OS: macos Version 10.15.7 (Build 19H2026)
App Info: AuthPass (1.9.7+1940) [design.codeux.authpass]
Device: {arch: x86_64, model: MacBookPro9,1, hostName: Darwin, osRelease: Version 10.15.7 (Build 19H2026)}