How can I make a right URL like mysite.com/articles/article1.html?

[Lucius]

I want to show my article like in this link mysite/articles/article1.html so that everyone can enter the URL and read my article. But every time I failed, only get an annoying 404 code: the requested URL /articles/article1.html can not be found on this server. I tried to create a folder called "articles" and put it in the folder "public_html", or in the root folder. Of course, I also created an artcle1.html and put it into the "articles" folder. Then I typed mysite/articles/article1.html and get the error 404.
Can anyone point my mistake out and correct me? Thanks all, I really tied because of it.

[skurudo]

It can be case sensetive filename, for example.

You can check things like this -> pub some index.html in public_html and see.