Hey,
if i’m opening the URL i’m getting the following error of Firefox presented:
Your connection is not secure
The website tried to negotiate an inadequate level of security.
cloud.bdevay.duckdns.org uses security technology that is outdated and vulnerable to attack. An attacker could easily reveal information which you thought to be safe. The website administrator will need to fix the server first before you can visit the site.
Error code: NS_ERROR_NET_INADEQUATE_SECURITY
opening the link with Chrome shows the following:
This site can’t be reachedThe webpage at https://cloud.bdevay.duckdns.org/ might be temporarily down or it may have moved permanently to a new web address.
ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY
It looks to me there is a new problem with the SSL configuration on the web server unrelated to ownCloud which seems to match this from your log file:
Maybe you can find some information on the internet about these errors and how to configure nginx with SSL correctly for your operating system (could be possible that some of the SSL configuration in the example nginx config are too new or too old for Ubuntu 18.04).