The WMCS integration MOFH has is considered to be broken, and Blesta has never been supported as far as I am aware. Of course you are more then welcome to try and get them to work, but personally I don’t think it is possible. 

Hi, I have a blesta billing panel setup and I unsure how to set the WHM API up with it. I am using the "cPanel" module provided by Blesta. I have whitelisted the server API and when I try to set it up I get an error saying the server cant be reached or the connection cant be established. Any ideas or help you can give would be muchly appreciated.

Your site does not utilize Cloudflare. This being known, it looks to be an issue on your users side. They could be using a VPN or something such as Cloudflare WARP, you should request that if anything such as these is active that they disable them and try again. If this does not fix it, their issue goes beyond the support you can provide and they should speak with their own ISP.

This:    

I don't understand why my website is protected by Cloudflare, because I didn't host my domain name on Cloudflare. My domain name was purchased from https://www.domain.com/, and the domain name resolution is also through https://www.domain.com/. My domain name seems to have nothing to do with Cloudflare, so how can it be protected by it? Can you help me figure out what's going on? Thank you! My website: https://freeaihosting.com