If you want to delegate your domain to other name servers, then the domain must be transferred out of Cloudflare first.
6.1 Nameservers. Registrant agrees to use Cloudflare’s nameservers. REGISTRANT ACKNOWLEDGES AND AGREES THAT IT MAY NOT CHANGE THE NAMESERVERS ON THE REGISTRAR SERVICES, AND THAT IT MUST TRANSFER TO A THIRD PARTY REGISTRAR IF IT WISHES TO CHANGE NAMESERVERS.
7.2 nameservers
Registrant agrees to use Cloudflare’s nameservers. REGISTRANT ACKNOWLEDGES AND AGREES THAT IT MAY NOT CHANGE THE NAMESERVERS ON THE REGISTRAR SERVICES, AND THAT IT MUST TRANSFER TO A THIRD PARTY REGISTRAR IF IT WISHES TO CHANGE NAMESERVERS.
I will suggest you to contact Kajabi, and request that they provide the relevant DNS record(s) (typically such as AAAA, A or CNAME), and then adjust your DNS record(s) so they match that instead.
According to their documentation, it seems like a CNAME record pointed towards “ssl.kajabi.com” may be all you need for the website.