It’s very important that your site’s A records are set correctly.
‘A’ records, or Address Mapping Record to use the full name, take your domain (yoursite.com) or subdomain (www.yoursite.com) and point it at an IP address (usually your servers IP address).
There can be many different A records. For example, foo.yoursite.com could point at one server and bar.yoursite.com could point at a completely different server.
Do not change A records unless you know what you are doing.
Changes to A records take time to propagate over the internet.
If you make a change and then realise you’ve done it wrong, you could be in for a 24-hour wait until it’s fixed.
‘A’ records and DNS are not strictly part of a WordPress website as they are more connected to your domain name, but seeing as you need a domain name to host your website on, they are here for reference.
One other thing to consider when setting up your DNS is to use Cloudflare – a DNS hosting service that can help to speed up your website as well as your DNS.