CNAME for .cloudflareaccess

Hi, is there a way to provide the .cloudflareaccess.com domain under an own subdomain?
e.g. if my company is ‘ironpeak’, I want to access ironpeak.cloudflareaccess.com under apps.ironpeak.be.

Defining a CNAME returns: Error 1014
Ray ID: 5e335f64be0bd4b4 • 2020-10-16 17:06:49 UTC

CNAME Cross-User Banned

Thanks.