All Virtual Host Sites giving "refused to connect" errors

I can’t figure this one out. Everything was running well. I don’t see anything in the access or error logs that indicate a problem (some of the sites don’t even have error logs yet).

Via Virtualmin, I can go to services --> preview website and then the site loads just fine.

If I try to access the same site via it’s URL, I get the refuse to connect error. Some are one domain, some are subdomains of that domain, some are completely different domains.

What should I be looking at to debug this?

This was weird. I rebooted and the problem fixed itself. It came on when I forced a scheduled backup. I suspect that the system ran out of memory and some process died that I didn’t find. Not diagnosed, but the problem is solved for now