phaxio.fax.create(faxParams) on Android causes application to crash #25

I'm using my testing key and secret to instantiate a Phaxio object. I'm then putting a url to a PDF document stored in Google Firebase Storage in my fax params, and then creating a fax.

        final Phaxio phaxio = new Phaxio(key, secret);
        String url = urls.get(0);
        HashMap<String, Object> faxParams = new HashMap<>();
        faxParams.put("to", OUTGOING_FAX_NUM);
        faxParams.put("content_url", url);
        Fax fax = phaxio.fax.create(faxParams);

When I press the button that I've linked to this sendFax() function, the application crashes. When looking through the LogCat, I found the error:

    java.lang.NoClassDefFoundError: Failed resolution of: Ljavax/xml/bind/DatatypeConverter;

From what I can understand, Android doesn't support javax.xml.bind.DatatypeConverter. Any possible fix for this? Thanks.