backup data is not moved to external storage

Hello dear community, I'm wondering if the "Backup" app creates any kind of logs? I can't get any further, I have configured the creation of backups.

Unfortunately, nextcloud only creates files in the app_data folder, the "Backup" folder remains empty... I haven't been able to successfully create a full backup yet.

I would like to get to the bottom of the error... I can't find anything in the actual nextcloud.log.

Maybe someone has a tip?

About the system:
Nextcloud 23.0.3
Backup app 1.0.6

my settings: https://ibb.co/6Dx04Nd

the backup runs without errors with the occ command:
> Maintenance mode: on
> Initialization of the AppData
> Initialization of the RestoringPoint: 20220411170259-full-qqnArAn23cdvuIk based on NC23.0.3.2
> Memory initialization
> Preparation of the data to be stored in the recovery point
> Preparation of internal data
> create blocks
* Data: /ncdata/ncdata/, 1055171 files
- Data-11821008-08de-4bec-80d4-508655271d1d
- Data-51204c06-5319-4e1d-ac78-573c85999f76
- Data-5946887d-d2c3-4a8e-a1fd-6944113e4c66
- Data-d01754b0-3766-44fd-8ea5-108511af571c
- Data-a04ae70d-f271-449b-a1e6-15fdfe8284bc
- Data-489233b8-9065-40a0-b0a1-0972c267f4c0
- Data-201200b3-8cd7-475c-8a50-c8c5d10d3454
- Data-da6a7e0b-311c-4462-b462-ff0466782baa
- Data-293933bc-e8bf-4f2d-8949-8fd3862160b4
- Data-c6c251ff-b6f2-4614-bf49-e66a70851547
- Data-c3088fca-2b0e-4bac-b005-d75a17ece88e
- data-ed0374af-9930-4d48-9d82-1b56fcc09b90
- Data-caffda23-5f32-4b2a-a9af-50069d955059
- Data-56d1043b-f351-49b5-a25a-8e7ab2ef0f26
- Data-c5fcfbaa-4e77-46de-b486-fbda9e65b282
> Maintenance mode: off

Regards!

No source file or test is named. Start by reproducing the configured backup with the reported occ command, review the Backup app configuration and available Nextcloud logs, and compare the app_data output with the expected external Backup location. Done means the cause of the missing external-storage data is identified and a backup is stored there or a clear error is logged.