UnknowHostException: Unable to resolve host “graph.facebook.com”
This error means, that something is blocking the access to the facebook url. If you use an ad blocker, you need to whitelist this link. If you use the internet connection of your employer, your employer may block access to facebook - in this case you can’t do anything, use your own internet instead. If you use a firewall or similar, you need to whitelist the link as well.
If this is not the issues for you, check out the documentation or contact me via mail.