NextCloud WebUI ssl error

Hello,

I am running NextCloud v32.0.5 (App version v2.1.28) on a MiniX+

Since updating latest versions in January (3 updates have been released this month).

when I click on “Web UI” in the Application info, I get the following error page: “This site can’t provide a secure connection 192.168.0.XX sent an incorrect response" then below “ERR_SSL_PROTOCOL_ERROR

External access with url like https://nextcloud.domain.com/index.php/login (via Nginx Reverse proxy and Let’s Encrypt certificate) is working fine

i have noticed that the settings “Certificate ID” in the App config page doesn’t save the “No Certificate” value. After selecting and saving, value is empty when opening again NextCloud App Config page. Could that be the cause ?
See screenshots below

Sorry if issue is obvious, i am newbie in TrueNas and NextCloud