Changes to nameservers not saving

I registered my domain through DreamHost, but my website is hosted on Wix. I’m trying to change the nameservers in DreamHost to etc. However, every time I type the change and press save, the field reverts to

I’ve tried changing the information in both Registrations (Modify Whois) and in DNS under Manage Domains. Neither will save anything I type. I’ve also tried using all three web browsers I have available (Firefox, Chrome, and IE) in case that had something to do with it.

What am I missing?

I’d contact dreamhost support. There is nothing magical and it sounds like you are doing what your supposed to, and the record ns1.wix.xom exists (I checked).