LibreNMS Virtual Image Networking Issue

I’ve installed the LibreNMS CentOS 7 virtual images on a KVM host using both a private network bridge (using the KVM default virtual networking) and a public network bridge using the commands hereat:

The first one, using a private network bridge, seems to work fine: I get the expected LibreNMS login screen. But I can only browse this locally from the host and other VMs on the same host.

Trouble is, I need to be able to access LibreNMS remotely, obviously! However, the public networking seems not to be working. I do get an error message from the Nginx web server “Whoops, looks like something went wrong. Check your librenms.log” so, something is getting through.

When I run validate.php it seems to suggest that it is a DNS issue for some reason. When I look at ip tables, only the private networking has entries.

What could be the problem please? I am new to both LibreNMS and KVM!