Sonarr copies episode but doesnt recognize it

Sonarr version (exact version): 3.0.3.899
Mono version (if Sonarr is not running on Windows): 6.10.0.104
OS: Debian 10 “Buster”
Debug logs:

20-7-14 07:33:54.9|Warn|ImportApprovedEpisodes|Couldn't import episode /mnt/sabnzbd/DestDir/Series/XXX/XXX.mkv

[v3.0.3.899] NzbDrone.Common.Disk.DestinationAlreadyExistsException: Destination /mnt/Serien/XXX/Season 01/XXX.mkv already exists.
  at NzbDrone.Common.Disk.DiskTransferService.ClearTargetPath (System.String sourcePath, System.String targetPath, System.Boolean overwrite) [0x0001e] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskTransferService.cs:328 
  at NzbDrone.Common.Disk.DiskTransferService.TransferFile (System.String sourcePath, System.String targetPath, NzbDrone.Common.Disk.TransferMode mode, System.Boolean overwrite) [0x00228] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskTransferService.cs:243 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.TransferFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Tv.Series series, System.Collections.Generic.List`1[T] episodes, System.String destinationFilePath, NzbDrone.Common.Disk.TransferMode mode) [0x00129] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:119 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.MoveEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode) [0x0005f] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:81 
  at NzbDrone.Core.MediaFiles.UpgradeMediaFileService.UpgradeEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode, System.Boolean copyOnly) [0x001ab] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\UpgradeMediaFileService.cs:77 
  at NzbDrone.Core.MediaFiles.EpisodeImport.ImportApprovedEpisodes.Import (System.Collections.Generic.List`1[T] decisions, System.Boolean newDownload, NzbDrone.Core.Download.DownloadClientItem downloadClientItem, NzbDrone.Core.MediaFiles.EpisodeImport.ImportMode importMode) [0x0029d] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeImport\ImportApprovedEpisodes.cs:111 NzbDrone.Common.Disk.DestinationAlreadyExistsException

Description of issue:
Well, kinda interesting (or I am just to stupid).
Those problems first occured after moving to my new Server and setting up Sonarr v3 instead of Sonarr v2. First of all i couldn’t establish a connection betwenn Sonarr and SABnzbd (but Radarr could). So i moved to NZBget, this was the beginning of all problems.

Besides the error log from above, NZBget downloads the file and puts it in the folder “DestDIR”. Sonarr renames it and copies to Plex, Plex is recognizing it.
But Sonarr is not logging that i copied to Plex. So Sonarr tries again to copy it but fails, because it got already copied. So the Episode in the Queue is marked as “Failed to import episode, Destination already exists.”. And in the series it’s marked as “Status: Import failed […]”.

What am i doing wrong?

Additional Information:
I can upload the whole log file, but it’s made out of only those errors for all my items in the queue.

Sonarr and NZBGet are installed in seperated LXC-Container.
They all get access to my raid with mounted Samba-shares, no problems with the permissions.

Hi, me again.

I tried to recreate the problem. Now i found a another Error before the “couldn’t import” error.

20-7-14 07:57:58.4|Warn|ImportApprovedEpisodes|Couldn't import episode /mnt/sabnzbd/DestDir/Series/XXX/XXX.mkv

[v3.0.3.899] System.UnauthorizedAccessException: Access to the path '/mnt/sabnzbd/DestDir/Series/X/XXX.mkv' is denied. ---> System.IO.IOException: Permission denied
   --- End of inner exception stack trace ---
  at System.IO.FileSystem.DeleteFile (System.String fullPath) [0x0006d] in <a17fa1457c5d44f2885ac746c1764ea5>:0 
  at System.IO.File.Delete (System.String path) [0x00014] in <a17fa1457c5d44f2885ac746c1764ea5>:0 
  at NzbDrone.Common.Disk.DiskProviderBase.DeleteFile (System.String path) [0x00067] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskProviderBase.cs:199 
  at NzbDrone.Common.Disk.DiskTransferService.TransferFile (System.String sourcePath, System.String targetPath, NzbDrone.Common.Disk.TransferMode mode, System.Boolean overwrite) [0x00482] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskTransferService.cs:307 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.TransferFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Tv.Series series, System.Collections.Generic.List`1[T] episodes, System.String destinationFilePath, NzbDrone.Common.Disk.TransferMode mode) [0x00129] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:119 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.MoveEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode) [0x0005f] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:81 
  at NzbDrone.Core.MediaFiles.UpgradeMediaFileService.UpgradeEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode, System.Boolean copyOnly) [0x001ab] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\UpgradeMediaFileService.cs:77 
  at NzbDrone.Core.MediaFiles.EpisodeImport.ImportApprovedEpisodes.Import (System.Collections.Generic.List`1[T] decisions, System.Boolean newDownload, NzbDrone.Core.Download.DownloadClientItem downloadClientItem, NzbDrone.Core.MediaFiles.EpisodeImport.ImportMode importMode) [0x0029d] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeImport\ImportApprovedEpisodes.cs:111 

Now it is telling me, Sonarr has no permission to access the file.
Funny thing is, the file got copied from Sonarr. But it does not appear in the log. And Sonarr has access to the file.
Here the permissions:

root@Serverr:/mnt/sabnzbd/DestDir/Series/XXX# ls -l
total 1398784
-rwxrwxrwx 1 root root 1431189401 Jun 25 13:41 XXX.mkv
root@Serverr:/mnt/sabnzbd/DestDir/Series/XXX# 

Every other user can access the file, but it still does not work. But why is the owner root?

After that, the same error occurs again.

20-7-14 07:58:12.5|Warn|ImportApprovedEpisodes|Couldn't import episode /mnt/sabnzbd/DestDir/Series/XXX/XXX.mkv

[v3.0.3.899] NzbDrone.Common.Disk.DestinationAlreadyExistsException: Destination /mnt/Serien/XXX/XXX.mkv already exists.
  at NzbDrone.Common.Disk.DiskTransferService.ClearTargetPath (System.String sourcePath, System.String targetPath, System.Boolean overwrite) [0x0001e] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskTransferService.cs:328 
  at NzbDrone.Common.Disk.DiskTransferService.TransferFile (System.String sourcePath, System.String targetPath, NzbDrone.Common.Disk.TransferMode mode, System.Boolean overwrite) [0x00228] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Common\Disk\DiskTransferService.cs:243 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.TransferFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Tv.Series series, System.Collections.Generic.List`1[T] episodes, System.String destinationFilePath, NzbDrone.Common.Disk.TransferMode mode) [0x00129] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:119 
  at NzbDrone.Core.MediaFiles.EpisodeFileMovingService.MoveEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode) [0x0005f] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeFileMovingService.cs:81 
  at NzbDrone.Core.MediaFiles.UpgradeMediaFileService.UpgradeEpisodeFile (NzbDrone.Core.MediaFiles.EpisodeFile episodeFile, NzbDrone.Core.Parser.Model.LocalEpisode localEpisode, System.Boolean copyOnly) [0x001ab] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\UpgradeMediaFileService.cs:77 
  at NzbDrone.Core.MediaFiles.EpisodeImport.ImportApprovedEpisodes.Import (System.Collections.Generic.List`1[T] decisions, System.Boolean newDownload, NzbDrone.Core.Download.DownloadClientItem downloadClientItem, NzbDrone.Core.MediaFiles.EpisodeImport.ImportMode importMode) [0x0029d] in M:\BuildAgent\work\63739567f01dbcc2\src\NzbDrone.Core\MediaFiles\EpisodeImport\ImportApprovedEpisodes.cs:111 

I solved myself the problem, it was again my fault at the config von samba.
Files were created with 755 not 777.
So Sonarr was able to copy the file but not delete the original. But there was no error log like that.