I've had a 3 pack setup for 3 years.  One of the satellites just stopped working, flashing blue.  It's wireless.  App says it's offline and can't be found.  I unplugged and replugged, updated firmware, did the replug again, then did a factory reset.  Still flashing blue.  Moved it closer to the main, still flashing.  Swapped it with the other satellite which is wired and working.  Still flashing blue even though it's now wired in.  The formerly wired one is working fine on wifi.  Not sure what is left.  I can't remove it from the network, I keep getting an error message that it can't be removed at this time and try again.  Can't add it as new, I assume because it is already assigned and can't removed it.  Is it garbage?  If so, do I have to get another M5 or can I buy a newer or different model to add to my network?  I need all three to reach the 2nd floor and backyard.