My client owns the domain but does not remember his cloudflare account credentials so we cannot log in to this account. We also do not know what email address the account was created with so we have no way to regain access. How can we get back this account not knowing credentials?
If they don’t work, then they will need to take control of the DNS by changing the nameservers at the domain registrar to point to those for a new Cloudflare account or other DNS provider.