I got the same message on all my networks with MR74, simply solved by settings the external currently installed on them
By default Meraki leaves it configured with MA-ANT-23 but seems to show the alert until you manually set the proper one as there are few possibilities
Note you have to do it on both radios.
![Jerome_EVAGroup_0-1599146422345.png Jerome_EVAGroup_0-1599146422345.png](https://community.meraki.com/t5/image/serverpage/image-id/14837i87E898F8A28350EE/image-size/medium?v=v2&px=400)
![Jerome_EVAGroup_1-1599146457532.png Jerome_EVAGroup_1-1599146457532.png](https://community.meraki.com/t5/image/serverpage/image-id/14838i174D95FDB9ACCB4D/image-size/medium?v=v2&px=400)
![Jerome_EVAGroup_0-1599146359668.png Jerome_EVAGroup_0-1599146359668.png](https://community.meraki.com/t5/image/serverpage/image-id/14836i34058BDEBF60F8CB/image-size/medium?v=v2&px=400)