OK, so once you have a chance, please collect WinSCP and FileZilla logs from the same machine in situation in which WinSCP fails and FileZilla works.
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
AUTH TLScommand, Pure-FTPd returns either "234 AUTH TLS OK." or "500 Unknown command" (when TLS is disabled).
This issue has popped up a few times recently, and we have done thorough testing to ensure that the issue isn't with our servers - and we found that the problem is client-side.
To be sure, I have just connected to your hosting service, using FileZilla on my end without issue.
What I can recommend doing is reinstalling WinSCP or consider using a different FTP client altogether.
We generally recommend using FileZilla for FTP.
The issue may also be related to your Windows 10 installation as there may have been an update that has caused these issues.
It is hard to say exactly what the cause is, however, I can certainly say that this isn't a server issue.