If you've just created/enabled a new RSS (or CAP) feed in Omnilert, the system will generate the URL for the feed in the Network settings.
That URL will be the home of your RSS or CAP feed on Omnilert's servers.
However, the RSS feed itself won't actually exist on that special URL until an initial message is posted. Once a message is posted, the requisite XML will be pushed out and the URL will resolve properly.
So, if you set up a new feed and go to the URL before ever sending, expect an "HTTP 403 Forbidden" error, as the directory on Omnilert's web server will be empty.
Send a test message to your new RSS or CAP feed.
Compose a new message, selecting only RSS (or CAP) and then post some content to the feed.
Once there's a message posted, the feed will have content and return a proper response to HTTP (and HTTPS) requests.
Tip: If you're setting up a connection to a 3rd party endpoint, like a digital sign, CMS/website, or another system with an RSS/CAP reader, you'll probably need a test message to complete your setup.