GenerateIIDForListItem returing null

I am new to CSR trying to code entire Sharepoint List row based on the status, but the code is returning null as shown below:

 for (var i=0;i<rows.length;i++)
       {
          var status = rows[i].Request_x0020_Status;
          var rowId = GenerateIIDForListItem(ctx, rows[i]);//return rowID as (0,421,0)
          var row = document.getElementById(rowId);//returns null
          if(status=="Rechazado")
      {}
          //row.style.backgroundColor = "#b1b1b1";
       }

Use this JSLink code to color entire row based on Request Status column:

<script type="text/javascript">
(function() {  
    var overrideCurrentContext = {};  
    overrideCurrentContext.Templates = {};  
    overrideCurrentContext.OnPostRender = HighlightProductRows;  
    SPClientTemplates.TemplateManager.RegisterTemplateOverrides(overrideCurrentContext);  
})();  


function HighlightProductRows(ctx) {  
    var statusColors = {  
        'Rechazado': '#b1b1b1',  
        'Pending': '#FFD800',  
        'Completed': '#01DF3A'  
    };  

    var rows = ctx.ListData.Row;  
    for (var i = 0; i < rows.length; i++) {  
        console.log(rows[i]);
        var status = rows[i]["Request_x0020_Status"];  
        var rowId = GenerateIIDForListItem(ctx, rows[i]);
        console.log(rowId);  
        var row = document.getElementById(rowId);  
        row.style.backgroundColor = statusColors[status];  
    }  
}
</script>

This is the render result and Developer Console data for rowId and row: