Hi,
When Kibana bootstraps, it will download geckodriver from a https URL. Is it possible your are doing this on a company network which blocks all requests outside of the local network if they are not going through a proxy?
If yes, setting HTTPS_PROXY and HTTP_PROXY environment variables before running bootstrap to your local proxy server should fix the issue: https://www.npmjs.com/package/geckodriver/v/1.14.1#setting-a-proxy-url