As above, please contact Meraki support.  In the meantime you can also start looking at your RADIUS server logs, Meraki event logs, and packet captures to understand where the issue lies in regard to client device authentication. ... View more

I experienced an issue with MR56s, essentially the MT would cease to use them as a gateway.  The following note from the 28.6 release notes specifies the MR42E and MR53E,  but in my case with the MR56 the issue was fixed with new firmware.   MT Sensors are unable to connect to gateway (MR42E, MR53E) ... View more