After seraching the web, it appears that certification rules were recently updated.

It also appears that certifications may be delivered and updated using a free service "let's encrypt".
This free service is declared compatible with the Dynu services.
How should a activate it for the certification of my domain gonze.org ?
I would be happy to read a guide about usage of dynu DDNS and "let's encrypt" (certbot).

Tnx in advance.