Denis
I think, I have found the issue.
Your WP theme includes own Font Awesome Icons with version 4.0.3 and has conflict with AGP Font Awesome plugin.
For resolving this problem, You can try comment or delete Font Awesome connection in the style.css file of Your theme:
File: themes/canvas/style.css
Lines ~: 174 – 179
Code to delete:
@font-face {
font-family: 'FontAwesome';
src: url("includes/fonts/fontawesome-webfont.eot?v=4.0.3");
src: url("includes/fonts/fontawesome-webfont.eot?#iefix&v=4.0.3") format("embedded-opentype"), url("includes/fonts/fontawesome-webfont.woff?v=4.0.3") format("woff"), url("includes/fonts/fontawesome-webfont.ttf?v=4.0.3") format("truetype"), url("includes/fonts/fontawesome-webfont.svg?v=4.0.3#fontawesomeregular") format("svg");
font-weight: normal;
font-style: normal; }
It will help.