Я получаю эту ошибку при попытке запустить CDN
external_css = ["https://cdnjs.cloudflare.com/ajax/libs/materialize/0.100.2/css/materialize.min.css"] for css in external_css: app.css.append_css({"external_url": css}) external_js = ['https://cdnjs.cloudflare.com/ajax/libs/materialize/0.100.2/js/materialize.min.js'] for js in external_js: app.scripts.append_script({'external_url': js})