Angular

As Aakash commented, your choices are to:

1. Use hash location strategy and let Angular handle the routing
2. Don't use hash location strategy and set up your server to always serve index.html (or at least fall back to serving that if whatever x.html isn't found)

This is because browsers/servers ignore anything after #'s. That means that linking to http://example.com/#/something will load example.com's index.html page (or whatever the server is set up to serve as default). Once index is served, Angular loads, reads the route NOT ignoring everything after the # and proceeds to handle the routing.

Without #'s, going to the same http://example.com/something will attempt to load something.html, which for an angular app doesn't exist so the server will 404. The server needs to be set up to serve the base index.html in such events. Once said index is served, Angular loads, reads the route and proceeds to handle the routing.