Hi I can’t add domain with sub_example.domain.com why ? I tested it from another panel or dns provider like cloudflare, there is no such error. can you help with this ?
Underscore is not allowed to be used in labels for hostnames. It is allowed for domain names but in this case you are adding a hostname.
- domain name is the identifier of a resource in a DNS database
- label is the part of a domain name in between dots
- hostname is a special type of domain name which identifies Internet hosts
So, don’t use underscore if you are adding a hostname.
Edit: Also, you won’t be able to create a certificate if your hostname contains underscore:
This is what was voted by CAB Foum:
After April 30, 2019, underscore characters (“_”) MUST NOT be present in dNSName entries.