I want: ping server on my PC by it domain name from remote.
I have:
I had a problem setting up DuckDNS as well. Here's some notes that would have helped me:
Be patient. Dynamic DNS support will update public records, but it take a bit of time to propagate to the DNS you're actually using. It took about 10 minutes before I was able to ping my public IP. Pinging my not work for you if you're dropping it, it all depending on what you're doing. You can also nslookup .duckdns.org. Once it comes back with your public IP you know it's working.
Time will tell if DuckDNS is reliable, but it works.