Error: Invalid host key (ServerShield from Cloudflare)

I’m trying to #activate my Cloudflare ServerShield account from my Plesk in my hosting at hostForLife.
Can not connect, I still have the message:
Error: Invalid host key.
I tried to create an account directly at Cloudflare, but I still can not start Cloudflare from my Plesk
Someone would have any idea ?
Thank you in advance.

That sounds like it needs a Partner Hosting API Key:

I have the same problem as I solve it, your link is broken

same problem from my cpanel. please guide me how to resolve the issue.
Thank you in advance.