System.NotSupportedException occuring
<p>I have this path which saves a excel sheet on the basis of date and time.
It is Showing 
<code>System.NotSupportedException</code></p>

<p>What is the correct Format ?</p>

<pre><code>   string strpath = Server.MapPath("~/SavedFolder/"+ username+ "/"+DateTime.Now+".xlsx/");
</code></pre>