URL Link not working on Internet Explorer

URL Link not working on Internet Explorer

I have been using this the Zoho Calender for our office. The HTML Link has been working great for other employees to view scheduling on our calendar remotely. Today when it was opened by one of the employees use the HTML link it wouldn't pull anything up. She was able to view it in Google Chrome but not Internet Explorer. Since Google Chrome is not available to outside Employee's, what can be done to get the calendar HTML Link working again through Internet Explorer. Most of the office is running on Internet Explorer versions 9 or 10.