Plugins not working on certain browsers

Hello,

I am using the Optimizer theme to create a website for my company. I have been using Firefox to build it; however, when the website was pulled up on Internet Explorer, none of the plugins appeared to be working correctly.

I have been using Magee Shortcodes to produce sections, buttons, etc. The content is still there when pulled up in internet explorer (including the buttons) but none of my formatting is present. Pictures are missing, as are dividers, section backgrounds, flipboxes, button formatting, column formatting, etc.

Here is the URL for reference: https://d1f.8dd.myftpupload.com/

Is there anything I can do to fix this problem? Any help would be much appreciated.