Error message when trying to change the nameservers of my custom domain

[EdwardHamHam]

Your domain name is of the .de TLD which means you’ll have to use CNAME verification instead.

How to add your domain with CNAME verification

If you want to host your own domain name with InfinityFree, the default way to verify your domain is to set the nameservers first. However, there are cases where setting the nameservers ahead of time is not desirable (for example if you have an existing site which cannot go down) or if your domain provider does not let you set our nameservers. Fortunately, InfinityFree now has the ability to host your domain name with us without having to change your nameservers ahead of time! This guide explai…