Short-code not generating calendar in various browsers

A client of mine needed an ORS on his website and I recommended Appointments+

A common problem for the users is that the plug-in seems to not work in many browser-environments. It seems to me the plug-in worked better before the latest upgrade, but I could be wrong - - it works fine for me in Chrome, but not in IE. See enclosed screenshots.

Can you help with this issue? Let me know it you need admin access to the site.