It's unlikely that it was fixed by a restart of your local machine.
Something must have changed on the server meanwhile.

Hi Martin,
Today, after rebooting my computer, WinSCP works (so far :) - I uploaded 4 or 5 files in the last 20 minutes.
The utility I used is File Manager from a web app called CP that web hosting providers use to enable their customers to do everything related to their hosted site.

Regards.

What is that utility like? Is it also an FTP client application? Or some web-based thing?
Can you post WinSCP session log file?

Hi,
I have been using WinSCP for some years now (2-3) to upload files to my hosted website.
Settings: FTP, Encryption TLS/SSL Explicit; Host name, Port# and Username already entered.
When I connect, I only input the password and then press the Login button to connect.
So far, no problems.

Problem:
I installed the software (a) manually (downloaded+installation) from website and, more recently (today), (b) downloaded from Windows Store and installed by Windows 10.

BOTH versions display the following error (starting from 30 mins ago) when I try to upload files:

Copying files to remote side failed.
Disk full - please upload later

I switched to uploading my files using the (less user friendly) utility of my Web Hosting Provider and it works flawless.

What is the problem?

Regards,
Mike