Dashboard reports that it cannot communicate to a Monitored Switch (9300)

[IronMike]

Within the Switching Dashboard of our monitored Catalyst 9300 switch, Meraki occasionally reports the it lost communication with that device and places it a dormie state.   On site, I can ping and ssh to the device.  Now it will come back online but in a unpredictable time period. 

What causes this?  I was also trying to upgrade the IOS on this switch but can't since Meraki lost connection to the switch? 

Any ideas on what I can do to prevent this from happening, because it looks like the switch is down but in reality it is in an up state locally.

Thanks

[Mloraditch]

Most fixes for the monitored switches involve removing them and then re-adding them.

In your scenario it's possible your firewall is blocking communications. Support may be able to diagnose what's happening when it happens. Do you have any Meraki managed devices connecting through the same firewall? Do they have similar outages?

You can check the firewall rules necessary by following this documentation: https://documentation.meraki.com/General_Administration/Other_Topics/Upstream_Firewall_Rules_for_Clo...

[cmr]

I agree with @Mloraditch, it does look like the firewall might be blocking something.  Are you in a position to monitor the outbound communications from the C9300s to see if anything is being blocked or timing out?