I ran into this same issue and after combining a couple of the answers above, your DNS configuration for example.com should be (with CNAME solving the www. issue):
A –> @ –> IP ADDRESS
CNAME –> * –> example.com.
NS –> ns1.digitalocean.com.
NS –> ns2.digitalocean.com.
NS –> ns3.digitalocean.com.
I am facing the same problem as you. I did everything in the tutorial and nothing seems to work. But I wait like an HOUR for this and then it works properly.
So this was my configuration, just as the tutorial in digitalocean here in the “CNAME” section
Enter Name: www
Enter Hostname: @
Hope it helps!!
PD: My droplet has this example name: example.com (or .net if your domain is .net, etc)