This can occur if you have exceeded the PoE budget on the switch. If you go:
Switches/Switches/[select switch]/Power Tab
It will show you your available budget and how much you have used.
![Screenshot from 2018-01-10 20-02-07.png Screenshot from 2018-01-10 20-02-07.png](https://community.meraki.com/t5/image/serverpage/image-id/1378iE184AC077D44F169/image-size/large?v=v2&px=999)
Failing that, what does the event log (next tab along) for the switch show when this happens?