Triggering TagManager PageView from Javascript

I am writing a Single Page Application. I am using the TagManager, and have configured a tag that watches for PageView triggers. My initial page load is recorded. When I update the URL and title with Javascript, I try to trigger a new PageView with javascript per the documentation: const evt = {'event': 'mtm.PageView'}; window._mtm.push(evt);.
However, the event doesn’t get logged at all, nor generate a call to the server.
Any assistance much appreciated,

Hi @craigmj
Did you configure the mtm.PageView event MTM side? Can you share how you configured it (screenshot)?