Fixed background image wont show up.

I am trying to put this photo (the blue people ) in the background. The second one is the one that is appearing on the internet. I used to have this up and now it is not working when I placed it on the internet. It even shows up in dreamweaver when i go live! Please someone help!

Here is a copy of my code:

.testimonial-section {

    padding: 80px 0;

    position: relative;

    background: url('../image-files/muscle-iq-ACTIVEa.jpg') center center fixed;

    background-size: cover;

    -webkit-background-size: cover;

    -moz-background-size: cover;

    -o-background-size: cover;

}

.page-banner-section {

    margin-top: 150px;

    padding: 80px 0;

    position: relative;

    background: url('../image-files/muscle-iq-ACTIVEa.jpg') center;

    background-size: cover;

    -webkit-background-size: cover;

    -moz-background-size: cover;

    -o-background-size: cover;

}