Currently, people with Mac Using 10.16 or higher cannot open or attend webex meetings. This seems to be a bug that was introduced in recent version of the Cisco Webex Meetings Web and Desktop applications. Numerous steps have been taken to troubleshoot this issue, yet the root source of the problem seems to stem from this updated version. We do have Single Sign On enabled with our local authentication authority just to level set on our agency's configuration. This is a serious problem that needs some Cisco WebEx developer insight to.