Missing icons in Block manager

Hi,

I have started using grapesjs and for some reason some of the icons from the Block Manager are missing.

I can see that the icons displayed use font awesome, while the icons not displayed have the classes "gjs-fonts" and for example "gjs-f-b1"

When looking at the CSS, I can find these styles:

.gjs-fonts::before {
    display: block;
    font: normal normal normal 14px font3336;
    text-rendering: auto;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-size: 5em
}
``

.gjs-f-b1::before {
    content: 'Q'
}

Why can't I see any icons? Am I supposed to add the icons manually or what do I need to do? Not sure it is related, but I also get a missing font error that I don't know where it comes from. The path not found is project/path/fonts/main-fonts.woff?v=20

Thanks for your help