Using Chrome, users getting the below error when previewing comments

System.ArgumentNullException: Value cannot be null. Parameter name: s at System.IO.StringReader..ctor(String s) at System.Xml.Linq.XElement.Parse(String text, LoadOptions options) at System.Xml.Linq.XElement.Parse(String text) at PrTrComONImg.Page_Load(Object sender, EventArgs e) 

Solution is the following: 

The teacher went to extension in google chrome (a little puzzle icon) and went to manage extension then adobe acrobat app and clicked on details.  Opened details and went to site access - and choose the option on click.  Default is on "on all sites" - change that to "on click".