SSRS returns HTML that is rendered by the web browser. If you're putting the CR/LF into an HTML string that is to be rendered/displayed, then unfortunately, the browser will ignore it.
You need to either send the line break HTML tag <br> or wrap your text in <p> and </p> tags. Or start playing with <div> tags, but that gets quite heavy quite quickly...
Thomas Rushton
blog: https://thelonedba.wordpress.com