title: ConfigurationErrorsException: Unable to load type ... because it is not public
body: <p>I am trying to access a custom section of the app.config in a windows service application.</p>
  
  <p>This is how I have defined the section</p>
  
  <pre><code>&lt;Configurations&gt;
   &lt;configSections&gt;
     &lt;section name="SectionName" type="ClassName, AssemblyName"/&gt;
   &lt;/configSections&gt;
   &lt;SectionName&gt;...&lt;/SectionName&gt;
  &lt;/Configurations&gt;
  </code></pre>
  
  <p>I get the following error</p>
  
  <blockquote>
    <p>An error occurred creating the configuration section handler for <code>SectionName</code>: Unable to load type '<code>ClassName</code>, <code>AssemblyName</code>, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' because it is not public.</p>
  </blockquote>
  
  <p>What could be the possible reasons for this error?</p>