Forticlient blocking Webex randomly

We use Forticlient 6.4.2 with ForticlientEMS 6.4.2 and we block the unrated web category. Randomly when trying to connect to a webex session it's being blocked by Forticlient because that traffic doesn't always use a categorized URL but an IP address. Since Cisco (Webex) has thousands of IP addresses it's not realistic to send a recategorize request to all of them. It's also not ideal to add exclusion to all IP adresses since we can't exclude subnets.

Any idea what we could do beside allowing the unrated category? We also allow "Allow websites when rating error occurs" so that's not the issue.

Thank you,