We recommend that you do not use a domain that you want to use as your custom branded email with CloudFlare (aka as the domain of your funnel), because it can be quite a complex process. Instead, we suggest having one domain name for your email and another for your funnel.
If you do not want to do this, then we recommend you contact your mail provider and ask how you can use the domain with CloudFlare while still maintaining your email service. CloudFlare also provides a starting guide on how to troubleshoot here.
Note: This is not something Client Concierge provides support with.