icons showing up as tiny boxes only on some devices

Hi,

Various icons on all my pages (e.g., social links, email, etc.). My website is
http://michaelcookllc.com/

I’ve seen previous posts about this – some suggesting I add code to my .htaccess file. I’m reluctant to dive into this process without more instruction.

The icons some times show up perfectly, and then I will refresh page and they are tiny boxes again…

Any help would be greatly appreciated!