Knowledgebase

Please try to update in your web.cofig file:

<configuration>
    <system.web>
      <httpHandlers>
          <remove verb="*" path="*.html" />
          <add verb="*" path="*.html" type="System.Web.UI.PageHandlerFactory" />
      </httpHandlers>
      <compilation>
         <buildProviders>
            <add extension=".html" type="System.Web.Compilation.PageBuildProvider"/>
         </buildProviders>
      </compilation>
   </system.web>
   <system.webServer>
	<handlers>
		<add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit-html" path="*.html" verb="*" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
		<add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit-html" path="*.html" verb="*" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
		<add name="ExtensionlessUrlHandler-Integrated-4.0-html" path="*.html" verb="*" type="System.Web.Handlers.TransferRequestHandler" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="0" />
	</handlers>
        <validation validateIntegratedModeConfiguration="false" />
    </system.webServer>

</configuration>