Cause:
This error occurs when Webex traffic is not allowed on the network, or if the incorrect username and password was entered into the proxy authentication window.

Solution:

Steps to resolve the issue:

1. Leave the meeting by going to the File menu, then selecting Leave Meeting or End Meeting.
2. Rejoin the meeting.
3. If an authentication window appears, enter your workplace network username and password.
4. If the issue persists, allow Webex traffic on your network. For help, see: WBX264 - How Do I Allow Webex Meetings Traffic on My Network?