Any ideas on what I should do? After doing some Googling and asking ChatGPT, it looks like my issue might have something to do with IPv6 compatibility or something like that. Unfortunately I'm not very knowledgeable about networking stuff, so I'm not sure how to identify or fix the issue.
SOLUTION:
I solved the problem by commenting out the line listen [::]:80 in templates/nginx.conf, and also commenting out the same line on the target server in /etc/nginx/sites-available/default.
It's not working, I'm still getting the same error. I don't know why it's still complaining about [::]:80 even though I commented that part out. Do I need to perform some kind of cleanup on the target server?