Thanks for the links. I saw only some of the links give a 404 error so I think it might be possible that you have a filter on the dynamic page but you’re not filtering the dataset on the properties page.
You can see I put it not to include News Title 03 and News Title 01 so those pages won’t be populated.
You can see then if you go to the test site, clicking News Title 01 or News Title 03 gives the same 404 error you’re seeing but the others work (it makes sense that we’re omitting those pages from being shown for now).