If you are getting the following message when you try to activate a domain, it means you have an active connection to a hosting partner already:

"If you are the new, rightful owner, please contact Cloudflare and reference this message (#208)."

If you are no longer with that hosting provider and would like us to remove the connection, please remove the connection by logging into your Cloudflare account

The option to remove the connection to the hosting provider is in your DNS settings.