if you have issue with failed to decode downloaded font: this way is the best for resolve it, i have tried it and work with re upload font awesome with zip and then unzip in the cpanel.
I just had the same issue – but with Font Awesome, which is a really well known font. Turned out this was caused by a problem with FTP. The file was uploaded as text (ASCII) instead of binary, which corrupted the file. I simply changed my FTP software to binary, re-uploaded the font files, and then it all worked.