Https blocking api communication between panels [help]

Hello

I need some help.

I currently use whmcs on a shared hosting using a module for my dashboard that is on a vps.

With HTTPS disabled, api can communicate normally.

More when enabling HTTPS from cloudflare, then whmcs loses communication with the panel.

The only way the communication works is if you use http on the panel.

How can I use https on my dashboard and whmcs was able to communicate without problems?

Thanks!

Google translator

Was your WHMCS accessible via HTTPS before you add Cloudflare?