One of our clients have stopped receiving E-Commerce tracking on their site. The checkout url that it was on has since changed. We have the Adobe Analytics tag on the page but there is still no data being captured.
I would put my money on the issue with e-commerce tracking disappearing having everything to do with your 404 page for the data layer file. You also mentioned that the URL structure has changed for the order confirmation page. Without knowing your current DTM setup, we can't really provide a thorough enough answer. The data layer is just a JSON object with an arbitrary name that holds key data points needed to maintain and sustain a successful analytics setup. How your DTM setup grabs these data points is what the question is so far. And, if your data layer is created through a file that is now receiving a 404 error, that should be the first thing you check for. Is your src value misspelled? Are you in the correct directory? Does the file even exist anymore?