DFS channels are a set of 5GHz channels that are commonly disabled in a default configuration. It is recommended in most circumstances to enable these channels, as the majority of the 5GHz bandwidth is contained within these bands. For more reading, see our article Understanding DFS Channels.
From the main Meraki dashboard, select Configuration and then RF/Radio in the Tags and Profiles section.
Select your Profile, in this case, the selection is High_Client_Density_rf_5gh
Select RRM
Select DCA in the RRM menu and then select DCA channels 36 - 161 which includes the DFS channel range.
Note: If using 20MHz channel widths, also select channel 165.