I have ordered a domaine called

When I try to update, at my registrar, the dns server name to enter my iworx ones I have an error. I already ordered a lot of domains at this registrar (domainsiste in fact) and I never had a pbm to edit the name server, but it’s the first time I order a dot name.

Is there something to know about this that I’d not ? something relating to iworx ?

I’m pretty sure not, but I have to eliminate all the possible cases