If you have viewers watching from a network that has a strict firewall service in places, such as a school or a corporation, they may need to whitelist a few domains in order for them to watch the event. You can find the detailed instructions from IBM Video website: https://support.video.ibm.com/hc/en-us/articles/207852107-Opening-Firewall-or-Proxy-Ports-for-IBM-Watson-Media-Broadcasting-and-Viewing