CloudFlare has a setup that uses their own IP's to proxy the address you are using. In short, they replace your IP with one of theirs. In order to get your CNAME record set up correctly inside Cloudflare, you need to bypass their server and make secure.pageserve.co the active CNAME record, as Cloudflare makes the domain appear as an A record.
If your current setup looks like this, you will have to click on the blue Edit dropdown and disable the default proxy from the orange toggle in order for the cloud to become grey/DNS only.
It will look like this after the change:
