How to find email associated with a certain domain

I’ve already utilized the “Forgot my username/email” option, where you input your domain name, and it sends an email to the address on file. Regrettably, we’re uncertain which email address received the message, as it might have been directed to an MSP/VAR email. Cloudflare is presently responsible for managing public DNS for themark8ing .com, and it’s crucial that we obtain access to oversee this for a project we’re currently engaged in. Your assistance would be greatly appreciated.

Are you referring to https://dash.cloudflare.com/login-help?