If you do something with let’s encrypt, always start with the staging area.
Let’s encrypt production area will block you for a week very, very quickly.
If you manage to get a staging certificate, then you move to the production area.
That way you also remove the problem of being blocked by too many requests.
Thanks Andrej, so your advice is remove rhe program including all the files inside reboot and start a new duckdns instalation starting with configuration.yaml?
If you are using multiple domains, you need to set an alias as per this old issue. Hopefully this puts you on the right path.
PS - regarding your “just waiting 2 days suddenly it started to work” part. You might need to reboot (not restart) your entire system for the changes to be picked up. At least, that’s been my solution when certificates don’t get renewed
My internet provider had me on CG-NAT system, this was the root cause i could not access to my domain. So i called to my company i submit a request to be out of CG-NAT and all start to work. Thanks for the support, step by step we finally got it.