Scan to SFTP share results in an emptry file #33

Describe the bug
Whenever I start a scan from a folder located on the Nextcloud instance, it works as expected (new file created, scanned image is stored in this file.
However, if I try the same from a folder which is located in a storage connected via SFTP, I get an empty file.

To Reproduce
Steps to reproduce the behavior:
Pre-condition: Mount SFTP in a folder 'SFTP'

1. Go to the folder 'SFTP'
2. Click on '+', 'Scan Image', enter the filename (e.g. '1.jpg')
3. When the scanner settings window appears, click 'Yes'
4. 'Scan started' message will appear. The printer starts scanning.
5. After a while an empty file '1.jpg' will appear in the folder. No error is displayed.

Expected behavior
Scanned image is stored into a file located on an SFTP share and contains scanned image.

Desktop (please complete the following information):

• OS: Win10
• Browser: Firefox 95.0.2 (64-bit)
• Version: NC 23.0.0.1