When you change DNS, keep in mind the following:
DNS zone changes need to be made if the domain's name servers point.
DNS zone changes are not immediate; they require time for propagation. Most records need 0-4 hours, but name server records require about 24-48 hours. For more information, see our Propagation Times article.
It's important to check the NS records and make sure they exactly match the name servers used at the domain's registrar (also known as "gluing"). If they don't match exactly, your website may experience intermittent downtime.
(See example picture below)
In this case, the nameservers for Miss Hosting are "nsX.misspark.se" and they match with the name servers shown at the registrar for this example-domain.