Not sure I get it. I have a virtual host with 4 sub-domains. When I try to “Backup Virtual Servers” the backup starts, then throws that error.
I have in fact only selected the top level virtual server in the backup routine, but the error persists with only that selected AND with all of them selected. No idea what this means.
Can’t help but for support they need more see https://www.virtualmin.com/node/53663
somewhere in backup settings, there is an option to proceed backup when errors occur, and not stop the whole backup process.
Problem solved. This was only happening on sites that I had set-up for reverse proxy that didn’t have sections in the conf files.