Every time I click the "Details" button in product page that I added, the message"We're sorry, an internal error occurred that prevents the request to complete.
Our supporting staff has been notified with this error and will address this issue shortly. We profusely apologize for the inconvenience and for any damage this may cause. You might want to try the same action at later time."
my log:
Message: Exception of type 'System.Web.HttpUnhandledException' was thrown.
Exception: System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.Web.HttpException: Cannot have multiple items selected in a DropDownList. at System.Web.UI.WebControls.DropDownList.VerifyMultiSelect() at System.Web.UI.WebControls.ListControl.RenderContents(HtmlTextWriter writer) at System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) at System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at System.Web.UI.Control.Render(HtmlTextWriter writer) at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at System.Web.UI.Control.RenderControl(HtmlTextWrite
How can I fix it?