SFTP login fails

Hi,

I am trying to set up an SFTP link to my NAS, but XCloner – Backup and Restore cannot connect.
I use the SFTP Username, the SFTP Password and I have indicated the location of the Private Key(RSA) which is the file /mnt/HDA_ROOT/.config/ssh/ssh_host_rsa_key.pub on my NAS.

Connection fails, although I can login to my NAS with Filezilla with the same credentials.

The error message is:
SFTP connection error: Could not login with username: xxxxxx, host: xx.xxx.xxx.xxx
The log states:
[2018-10-02 13:06:26] xcloner_remote_storage.INFO: Creating the SFTP remote storage connection [“”] []
[2018-10-02 13:06:26] xcloner_remote_storage.INFO: Checking validity of the remote storage SFTP filesystem []

What do I do wrong?

Regards,
Toon