Problem with let's encrypt?

I can’t connect my linux (opensuse) Nextcloud client to my Nextcoud account on o2switch, managed by cpanel.
I have no problem with Firefox or Chromium connexion, but my opensuse linux nextcloud client fails connecting.
The client works perfectly with an other server (yunohost). When I try to add the new one, using “add an account”, autenticate on your Nextcloud, I give my nextcloud URL (login url), the browser starts and I have a certificate error about my let’s encrypt certificate (created by cpanel :-(). I clic on “accept anyway”, have the login prompt on firefox, log, have a message “your client should works”, but the client do not receive or accept the answer and bring me to the error windows.
Of course the let’s encrypt certificate is up to date (until end of December).
Webdav link is not accepted.
any clue?

Bon, vérification faite, c’est une erreur de softaculous, netcloud ne peut pas fonctionner sur ce serveur :frowning:
pardon pour le dérangement

Really not supported on Softaculous? What about this thread from @cai ?

the error is to have given the option of a software forgiven by the hosting (o2switch). It’s a softaculous instance hosted on cpanel by o2switch