Don't you think reserving only 5 Mbps is too low? I believe that, depending on the number of users, this transfer rate is insufficient, especially if they are using video during the meeting.
Have you tried increasing the limit or removing this restriction?
Regarding the compatibility issue, there's not much we can do besides suggesting you update your browser or use a different one.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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