YNH subdomain on a different server

What type of hardware are you using: Old laptop or computer
What YunoHost version are you running: 12.0.17
How are you able to access your server: The webadmin
SSH
Direct access via physical keyboard/screen

Describe your issue

(English bellow)

Bonjour,
Je souhaite dédier un second serveur (dans un autre lieu) aux sauvegardes de mon serveur principal mondomaine.ynh.fr. J’aimerais assigner à ce second serveur le domaine backup.mondomaine.ynh.fr.
Le diagnostic du second serveur me dit que l’enregistrement DNS est incorrect : la valeur actuelle est en effet l’IP du serveur principal mondomaine.ynh.fr et non son IP.
Est-il possible de configurer manuellement les enregistrements DNS des noms de domaines offerts par YNH ? Ou existe-t-il une autre astuce ?

Hi,
I want to dedicate a second server (in a different location) to backups of my main server, mydomain.ynh.fr. I’d like to assign the backup.mydomain.ynh.fr domain to this second server.
The diagnostics for the second server tell me that the DNS record is incorrect: the current value is the IP address of the main server, mydomain.ynh.fr, and not its own IP address.
Is it possible to manually configure the DNS records for domain names offered by YNH? Or is there another way?

Share relevant logs or error messages

https://paste.yunohost.org/raw/oforuyexoc