Hi Guys, here is what ended up practically solving the issue for us. But it is more of an art than a formula since different Switches (MS390 vs MS125) ended up with different settings. 1. Port Isolation - Enabled 2. Link Negotiation - 1 GB Fixed to the MR30H 3. Flood unknown multicast traffic: try Enable / Disable and see if helps.   A firmware upgrade was important since Meraki added Multicast Queuing. Let me know if this helps.       ... View more