My website Shows a 404 error on certain browsers but available on others

I have this website built on nodejs express framework,hosted and working perfectly on certain browsers.I understand the responsiveness depends on the web browser version and if my code supports such a browser,but for some reason,my website in completely not loading on some browsers i.e Opera mini mobile browser. It throws a 404 error which I understand means web page not found.What could possibly be the issue?