What Josh said, but also, I’ve had a situation where I had to run an IcoMoon export through Font Squirrel (http://www.fontsquirrel.com/) to get it to work in Firefox as well. So try that if you’re font is actually local and not working.
I ran into this same issue, and this fix only worked on FontSquirrel’s Basic settings (ie this setting: ‘Straight conversion with minimal processing.’). Optimal and Expert processing gave me back empty files. Hopefully this saves future searchers some time.
Same issue, works fine on local with Firefox (Mac os) but not on live site. Re-upload font to FontSquirrel Webfont Generator still having the problem after that…However, its working fine on other computers just not mine..
@gin85cc I was having the same issue on Firefox. Worked on local setup but not on my WPengine server. I ran the TTF through Font Squirrel (Basic ettings) and now it works fine. The one thing is you have to go into IcoMoon’s style.css file and change the font family from ‘icomoon’ to ‘icomoonregular’, as Font Squirrel seems to name it differently. Hope that helps.