I have entered the IP address on the auerdev.com/auerdev.de Domain and this work. But when I create an “www” subdomain with the same IP address it don’t work. Another subdomains with the same IP work. When I deactivate cloudflare on that “www” subdomain it works but with cloudflare not.
I replied via the ticket just now but can confirm here that this was caused by these subdomains still being used as Custom Hostnames (SSL for SaaS) by a SSL for SaaS provider:
In a case like this, you need to contact the SSL for SaaS provider to manually remove the Custom Hostnames from their zone, so you can use them with your zone settings applying, as intended.