CloudFlare vs GCP not work for both http and https

I have followed exactly what described here https://support.cloudflare.com/hc/en-us/articles/204764348-How-to-use-Cloudflare-with-Google-Cloud-Platform
But I still can not connect to my VM in GCP
My temporary server is Instance, I can connect it directly but using CloudFlare DNS, I can not

That port is not supported by Cloudflare. You need to switch to one of the supported ones. Please use the search for more details.

Thanks, changed to supported ports, it works now