When adding a subdomain, it shows an error message: ‘This domain already exists as a child domain. [404],’ even though the subdomain does not exist or has not been added. I checked the vhost to ensure that the subdomain does not exist.
Example of the subdomain I added: wvww.mydomain.com
Point you server IP to A Record and mention @ (ip) on your nameserver.
repeat
Point you server IP to A Record and mention www on your nameserver.
if you don’t understand share me your domain here i will guide you how to setup it.
check this out [TUTORIAL] How to change website domain or subdomain and try check you url with cononical on this tool https://redirectchecker.com/ might you find any redirection issue
Thank you but that is not the answer.
it is wvww not www
Also I found the answer I just manually added it to the vhost