Missing file when syncing

I reconfigured syncing between Mac and IPad and iPhone and I always receive a « missing file » message in the journal.
the file name is unknown and rare so I don’t recognize it as a file of mine. I don’t know where to search to delete this strange file. I just would like to delete it but no option to delete it on DT to go nor on DT3

I add that I emptied fully my inbox database and emptied trash. verified db and no error . but when I start sync I get the same missing file error in the journal

This is a file in a sync store, not one of your databases. What kind of sync location do you use, did you verify the sync store (not the database)? See contextual menu in Preferences > Sync

I am using iCloud (Cloudkit)

And did you verify this sync store as suggested?

what do you mean by “verify sync store”? when I right click on inbox db in the pref/sync I can “verify db”, “clean db”

Right-click on the sync location and use Verify Location Quickly.