Here’s a very quick “how to” post on how to find your domain’s authoritative nameserver.
I’m writing this because if you made a DNS update and it didn’t work, there are 2 options:
Your authoritative nameserver doesn’t have the correct record
Your authoritative nameserver does have the correct record, but an old record is cached and you need to wait for the cache to expire
To be able to tell which one is happening (do you need to make a change, or do you just need to wait?), you need to be able to find your domain’s authoritative nameserver and query it to see what records it has.
[Very helpful. Noted!]