When I open a specific website, I am switched to my router’s password web page. Why does this happen? [duplicate]

When I open a specific website, I am switched to my router’s password web page. Why does this happen? [duplicate]

My router is Huawei MT880. When I open the my website that i m hosting, a dialog box asking for my router password appears. I am also using Apache webserver for publishing my own website. I have also register a free domain, that is pointing to my routers IP.