Font Awesome in html2pdf.js did not show

I putted html2pdf.js in my project,

https://github.com/eKoopmans/html2pdf.js .

And too I putted Font Awesome in my project,

Before pdf

After pdf

Why did not show the font awesome after output the pdf?

this is my codes

<script src="{{ asset('js/html2pdf.bundle.min.js') }}"></script>
<script>
    function generatePDF() {
        const element = document.getElementById("invoice");
        let opt = {
            filename:     'resume.pdf',
            image:        { type: 'jpeg', quality: 0.98 },
            jsPDF:        { unit: 'in', format: 'letter', orientation: 'portrait' }
        };
        html2pdf()
            .set(opt)
            .from(element)
            .save();
        {{--location.replace("{{route('index')}}");--}}
    }
</script>