@Font Face doesn't work!

Hello!

I am a newbie to CSS and so I used @font face code to add Proxima Nova and this is the code:

@font-face {
    font-family: 'proxima_nova_rgregular';
    src: url('proximanova-regular-webfont.eot');
    src: url('proximanova-regular-webfont.eot?#iefix') format('embedded-opentype'),
         url('proximanova-regular-webfont.woff2') format('woff2'),
         url('proximanova-regular-webfont.woff') format('woff'),
         url('proximanova-regular-webfont.ttf') format('truetype'),
         url('proximanova-regular-webfont.svg#proxima_nova_rgregular') format('svg');
    font-weight: normal;
    font-style: normal;

}

h4 { font-family: 'proxima_nova_rgregular', Helvetica, sans-serif; }

I don’t understand why it doesn’t get put in or I did something wrong… can some one help?

Thanks!