Assume that you run the Set-OwaVirtualDirectorycmdlet to set the value of the FilterWebBeaconsAndHtmlForms parameter to DisableFilter. When you view an email that contains HTML forms in its body in Microsoft Outlook Web App in a Microsoft Exchange Server 2013 environment, the forms aren't displayed.
Note By using the DisableFilter parameter setting, you can enable all potential Web beacon content in Outlook Web App.
This issue occurs because HTML formats aren't included in a normalized email body in Exchange Server 2013.
To fix this issue, install Cumulative Update 10 for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.