How to run Cloudflared under web proxy

My network is behind a web proxy

I have setup proxy proxy for http/https access via proxy configuration
I also have tried to create windows system variable
https_proxy with the value of web proxy path including http:// prefix

But Cloudflared service on the windows still unable to connect to Flarecloud and the tunnel is still keeps offline

Checking the traffic from the firewall, I can see traffic to flarecloud IPs keeps running directly but not go through webproxy
Other web traffic from webbroswer are going via webproxy and working OK

Please advise how to setup cloudflared service to pass data through web proxy

Thank you