@font-face failed OpenType embedding permission check. Permission must be Installable

sibaspage answer pointed me into the right direction. But I still see the error message in IE11. For me it worked using the following syntax:

@font-face {
   font-family: 'Font-Name';
   src: url('../fonts/Font-Name.eot?#iefix') format('embedded-opentype'),
        url('../fonts/Font-Name.ttf')  format('truetype');
}