I am using DuckDNS and it’s working perfectly for me. I use the DynDNS feature of my Fritz!Box to update my DuckDNS-IP. The documentation on their website is spot-on for me, even for my IPv6 and I never had any issues with DuckDNS.

What I like most about the service is the possibility to use subdomains like my-service.my-username.duckdns.org. I don’t know whether this is a commong feature or not.

When you had problems updating your IP Adresse did you consider that DNS information takes some time to propagate through the internet? I think it is not guaranteed that you can access a recently changed domain.

How did you test your DuckDNS entries?