NGINX is a reverse proxy service on Plesk. I’ve beaten my head against it a few times now. The most recent was when I added a static IP provided by my ISP and assigned one domain. Initially it worked but after a couple of weeks I realized that no hosted site was running. The error thrown up by the browser was the server was unavailable (not responding). When I checked my Plesk server I discovered that the Apache service was running, but NGINX was not, and nothing was listening on port 80.
Repeated attempts to start NGINX failed, citing issues with binding to the new IP I’d put in.
My initial concern was to get the sites up again. I went into Server Tools – IP Addresses – but found nothing wrong. So I rebooted the server. When it came back up I went back into IP Addresses and found that the new static was not working correctly and to ‘repair’ it. I ran the repair, everything seemed fine, but still the same errors with NGINX.
I reassigned the site to the old IP address and removed the IP from IP Addresses. Still, after a reboot, port 80 was still down and NGINX was still complaining about not being able to bind to the new IP (now non-existent).
I found these two commands (shell):
/usr/local/psa/admin/bin/nginxmng -d/usr/local/psa/admin/bin/nginxmng -e
Running the first command then the second forced NGINX to rebuild the proxy configuration for all sites. The second enabled the service (and started it). I then checked my sites and found they were all up again.
More information about resetting NGINX can be found here: https://support.plesk.com/hc/en-us/articles/213944465-Unable-to-start-or-enable-nginx-as-proxy-99-Cannot-assign-requested-address
