Domain user cannot delete own files

hi, I hooked the active directory to truenas
I have provided access credentials to a dataset
With domain users I can read, create new files. But I can’t delete old files

I upload correctly the file: Supremo.exe
I try to delete:

As an error I read in the popup: ‘to perform the operation, authorization from MEDE'user1’ is required.

Which is the domain user who uploaded that same file 2 minutes earlier …:-/

[root@TRUENAS-1 /mnt/POOL1/MEDEXPERT/SOFTWARE/VEEAM]# ll
total 7709059
drwxrwx—+ 2 root MEDE\domain users uarch 6 Oct 28 15:42 ./
drwxrwx—+ 7 root MEDE\domain users uarch 7 Oct 28 13:18 …/
-rwxrwxr–+ 1 MEDE\administrator MEDE\domain users uarch 13802120 Oct 28 10:21 Supremo.exe*

Where do you think the problem lies?

What is output of getfacl <path to file>?

root@TRUENAS-1[/mnt/POOL1/MEDEXPERT/SOFTWARE/VEEAM]# getfacl ./Supremo.exe

file: ./Supremo.exe

owner: MEDE\administrator

group: MEDE\domain users

group:MEDE\domain users:rwxpDdaARWcCos:------I:allow
user:MEDE\administrator:rwxpDdaARWcCos:------I:allow
owner@:rw-p–aARWcCos:-------:allow
group@:r-----a-R-c–s:-------:allow
everyone@:r-----a-R-c–s:-------:allow