When the web team designs a form using Live Form, if they use the Html control and enter text in Rich Text Edit mode which in turn make the form having html markup for formatting, then the Save and Return button will not work and the Html control is not saved, not post back occurs at all when users click on the Save and Return button. The error show:
2018-04-03 15:42:55.369-07:00 [WEBSERVER][D:2][T:83][FATAL] DotNetNuke.Web.Common.Internal.DotNetNukeHttpApplication - System.Web.HttpRequestValidationException (0x80004005): A potentially dangerous Request.Form value was detected from the client (FormData="...e,"Html":"<h4><span class=\"te...").
at System.Web.HttpRequest.ValidateString(String value, String collectionKey, RequestValidationSource requestCollection)
at System.Web.HttpRequest.<>c__DisplayClass5.<ValidateHttpValueCollection>b__3(String key, String value)
at System.Web.HttpValueCollection.EnsureKeyValidated(String key)
at System.Web.HttpValueCollection.Get(String name)
at System.Collections.Specialized.NameValueCollection.get_Item(String name)
at Mandeeps.DNN.Modules.LiveForms.Handlers.Designer.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
This error did not happen when the Live Form module is installed on the server 2008 R2 but when the site is porting over to server 2012 R2, the error occurs. If using the same Html control but in Basic Text mode or remove all the markups generated from the Html editor then the Save and Return button will work and the Html control is saved on the form design.