I've set up an trigger in GTM that tracks a 404 event. This shows the 404 page as the event action and the page the 404 was found on as the page label.
This works perfectly excluding the fact that any 404's found within my own website don't show the referrer in the label.
Presumably this is an issue with analytics rather than tag manager but why do my own pages not show as a referrer and how can I get it to do so?
{{referrer}}
should be the previous page in all cases and should work within your own site: support.google.com/tagmanager/answer/6106899?hl=en#web_example