Cannot Go to Next Month On Calender widget

Calender has been working fine, nothing has changed. I cannot move forward and view after Jan 31st calender just stalls and nothing shows up on page just the url – no content. I can move backwards in time and it’s fine. I can also use the search form to find the 1/2/2013 but not via the widget. I have used it previously to see other dates but all of a sudden nothing.

https://www.ads-software.com/extend/plugins/calendar/