@unclphil Zoom doesn't have any logic dictating a way to lock specific types of devices from joining meetings.
If your users are having issues joining, they may have been removed from the meeting previously, input the incorrect meeting password too many times, or they may be blocked for terms of service violations.
Please have your participants having issues attempt to join from the web browser to gain entry until the issues with their Mac device can be resolved.
Reference: https://support.zoom.us/hc/en-us/articles/201362193-Joining-a-Zoom-meeting If they were locked out due to incorrect password attempts, they can attempt to join again after 30 minutes. If they were removed previously from the same meeting ID, the host can visit their "Settings" tab in their Zoom web portal and enable the setting "Allow removed participants to rejoin." Once they start the meeting again those users can join without issue. If the meeting is locked, the host can unlock the meeting via the security tab in the meeting window.
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