Value cannot be null. Parameter name: uriString
<p>I recently created an application in Visual Studio 2015 following the link:
<a href="https://azure.microsoft.com/en-in/documentation/articles/documentdb-dotnet-application/" rel="noreferrer">https://azure.microsoft.com/en-in/documentation/articles/documentdb-dotnet-application/</a></p>

<p>But when I build the solution, it showed me the following error:</p>

<blockquote>
  <p>Value cannot be <code>null</code>.<br>
  Parameter name: <code>uriString</code><br>
  Line 71: <code>public static void Initialize()</code><br>
  Line 72: <code>{</code><br>
  Line 73: <code>client = new DocumentClient(new Uri(ConfigurationManager.AppSettings["https://&lt;db-name&gt;.documents.azure.com:443/"]), ConfigurationManager.AppSettings["&lt;db-key&gt;"]);</code><br>
  Line 74: <code>CreateDatabaseIfNotExistsAsync().Wait();</code><br>
  Line 75: <code>CreateCollectionIfNotExistsAsync().Wait();</code>  </p>
  
  <p>Source File: <code>C:\Users\BHAVIN PATEL\Documents\Visual Studio 2015\Projects\documentdb-dotnet-todo-app-master\src\DocumentDBRepository.cs</code>    Line: 73 </p>
</blockquote>

<p>I have inserted the URI and Primary/Secondary Key in <code>Web.config</code> file of my application from the DocumentDB application created in Azure. </p>