If you receive this error while attempting to make changes to your domain's name servers, it means the registrar rejected the names you provided. There are several reasons why this can happen:
- The "new" name servers aren't different than the old ones.
- The domain is locked, expired, or suspended.
- One or more of the requested name servers hasn't been registered.
(Where possible, our system will give you the best information it can about the reason for the problem.)
These are pretty self-explanatory, except for the requirement that name servers be registered. If you want to use a name server like ns1.example.com, that name needs to be registered as a child name server (along with its IP address) by the registrant of example.com in order to create the necessary NS pointer records ("glue records") at the gTLD registries. If you got these name server names from someone else, check with them to ensure the names have been registered as name servers. If you registered the domain containing the name server names here and now need to create new child name servers, see this FAQ entry for instructions.
Unfortunately, the error response they return is often neither human nor machine readable, so it does not indicate which of these is the case in a way we can automatically display. (Note: this issue is substantially less prevalent than it used to be.) If you are a subscription member and you do hit an error our system cannot decode, we can manually look it up for you in our logs and convert it to a human-readable explanation; just open a support issue.