ISSUE
Users may encounter an error stating, "You cannot connect to audio or video because we cannot validate the security certificate for your Webex site." When attempting to join a Webex meeting with audio or video, this error prevents users from establishing a secure connection to the Webex service, thus affecting their ability to participate in the meeting with full functionality.


RESOLUTION
To troubleshoot this issue:

• Verify if the following certificate is present on your computer:
  • IdenTrust Commercial Root CA 1
• If any of these certificates are missing, contact your IT Helpdesk for help adding them.
• If the above certificates are present, the network administrator must allow the following:
  • *.identrust.com

CAUSE
The error is typically caused by the customer's network blocking access to the domain `*.identrust.com`.
Starting from March 31, 2021, the Certificate Revocation List (CRL) for Webex services is hosted by IdenTrust, which requires the domain to be accessible for security certificate validation. If the domain is not allowed, the Webex client cannot validate the security certificate, leading to an error message.