My Crystal Report always appears blank

I use Visual Studio 2012 Ultimate and the latest version of Crystal Reports.

But every time I run the page, even the localhost report is blank. By viewing the source code of the page I can see all the information about it. It just does not throw this information in the form of a report.

Any ideas?

Follow the code as requested:

Aspx

<%@ Register Assembly="CrystalDecisions.Web, Version=13.0.2000.0, Culture=neutral, PublicKeyToken=692fbea5521e1304" Namespace="CrystalDecisions.Web" TagPrefix="CR" %>


      <form id="form1" runat="server">
         <div>
            <CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" AutoDataBind="True" />
         </div>
      </form>

ASPX.CS

protected void Page_Load(object sender, EventArgs e)       
{            
    ReportDocument rptrel = new ReportDocument();
    rptrel.Load(Server.MapPath("Rel_ComissaoInadCanc.rpt"));    
    CrystalReportViewer1.ReportSource = rptrel;
    CrystalReportViewer1.DataBind();
}