We’ve been doing quite a few server migrations recently and ran into a few peculiarities with changing nameservers on Namecheap. First and foremost:

No trailing periods (.)

AWS Route 53 and other hosting providers will give you NS records with a trailing period. If you use a trailing period in a nameserver record for Namecheap you’ll get a very generic error that doesn’t tell you what’s wrong.

A few other things:

  1. The name of the name server should be provided without spaces in the beginning as well as in the middle of the name servers hostname (e.g. as “ns1. nameserver.com” may result in error, while “ns1.nameserver.com” will be accepted).
  2. The name server should be provided without the trailing period in the end (e.g. as “ns1.nameserver.com” but not “ns1.nameserver.com.”).
  3. Name servers should be provided in the fields without their IP addresses.
  4. Name servers should be properly registered, i.e. it is possible to point a domain only to an existing name server.