Things that might be happening:
You are hiding the RG on page load.
Some element is in front of your RG, obscuring it from view.
You are changing the source of the RG on page load to a null list, making it collapse into nothingness.
Other things on the page are pushing your RG down the page (I.e., have you scrolled down the page in search of your RG?)
Your responsive settings are pushing the RG put of view (either to the left or the right).
Many other things, but that’s a start.
Want a sure-fire way to debug without relying on the peanut gallery here? Do this:
Turn on the option to add HTML IDs to elements. Now, open the edit settings for your RG. Scroll to the bottom of that dialog. You’ll see the HTML ID setting. Give the RG an ID of something memorable, like WTFRU.
Load your preview. Open your developer tools (F12 in most browsers), go to the elements pane. Hit control-f (for find). Find WTFRU.
There’s your RG.
Short of this, style your RG to have thick, bright colored borders. Even if the RG is collapsed, you’ll see a thick bright line. That would be your RG with no items in it.
(Note: if it’s hidden, you’ll see nothing of course.)
This is one of the problems with visual programming systems: unless you point us to your rendered page (or better, your publicly available Edit page) we can’t generally help you with questions like this.
(“Where’s my RG?” “I don’t know… where IS your RG?” is the answer. At least point us to the URL of your page, right?)