Block as follows - outbound: UDP Any Any Any 443,80   You can verify it's working by doing the following before creating the rule using Chrome. Go to youtube.com and in Chrome open Developer Tools -- Security -- Look for "QUIC" under Connection.   Once you have created and saved the rule and given the MX a minute or two to pull down the changes, hard refresh the page and where it said QUIC originally it should now say TLS 1.3 or similar. ... View more