thats’s more likely a fqdn aka server name with domain. (just wording. but not to get confused. since there is an ip address in your screen shot.)
do you have a screenshot of the error message?
did you include http://… in the trusted domain arry?
did you try a default web server page instead of nextcloud. just to check if you don’t have a routing problem.
and i think the is not necassary. just remove that first. but it might not be related to your problem.
is not necassary. just remove that first. but it might not be related to your problem.