Firewall / Communication Server Configuration:
Please find instructions on correcting the communication server port error that you are experiencing.
In the case that you have a firewall in place, users would need to add an exception for join.onstreammedia.com into the firewall program.
If you do not have a firewall in place or the above recommendation does not work, IT would need to grant access to the following ports (Ports 80, 443 or 1935). This would need to be done for RTMPE traffic along with standard web traffic.