Background image responsive

I can not make the image of my header responsive, I am using the following styles:

.page-header{   
background: url(../imagens/rock-in-rio-eu-vou.jpg) no-repeat center center fixed;
margin:0px;
height:590px;   
background-color: #ffffff;  
background-size:cover;
position: relative;

}

I used the same style in other pages and it worked, but now I can not ...