WinSCP Proxy Command with cloudflared

Hello, I'm trying to run this command as a ProxyCommand over SFTP
Although it doesn't seem to do anything, am I formatting it wrong or do I need to try something else?

I am using WinSCP Version 5.17.5 (Build 10414).

I've fixed the problem, I was using OpenSSH private keys instead of importing a PuTTY conversion.