The LED on the Mist AP can be very helpful if it ever has a problem connecting to the cloud. It will blink out error codes to explain exactly what the problem is. Below is a chart of these codes or you can have someone take a short video of the sequence and send that to Mist support.
If you are experiencing AP Disconnect issues and observe an LED pattern, please refer to this guide to help with troubleshooting:
https://www.mist.com/documentation/troubleshooting-ap-disconnect-issues/
