Sonarr permission issue - unable to determine if files is a sample

Sonarr version (exact version): 20190320-15
Mono version (if Sonarr is not running on Windows): 5.18.0.240-12
OS: synology
Debug logs: https://pastebin.com/ebHNjEvR
Description of issue: unable to determine if files is a sample

Hey there, maybe somebody can help me out.
I got an issue with permission rights with sonarr and nzbget on a synology.
When I download something with nzbget and the download is done its in the dst folder. From that sonarr should rename it and move it over to my media folder but somehow it’s not happening.
If I log in via ssh and change the permissions of the file to sc-nzbdrone with “sudo chown -R sc-nzbdrone /volume1/…” Sonarr recongnizes the file instantly and is doing the renaming and moving. Everytime I download a new file in the file is stated the the owner is nzbget.

What I already tried:
chown -R on source folder
chmod 777 -R on source folder as root
checked that sc-nzbdrone is in same group as nzbget -> sc-download
giving read/write permissions to group sc-download
reinstalled sonarr

I already found a thread on the sonarr forum about it.

So far I couldn’t get it running. I’m running out of ideas.
thanks for the help