My Deco network has a combination of S4 and M5 units.  Up until yesterday I had the S4 as my base station. I have now experienced two of my three S4 base station units suddenly turn red and fail to connect to my router.  After trying multiple times to reboot both the router and the base station I have had to completely set up a new network swapping out the failed unit.  The first time this happened about a month ago I used another S4 for the base station.  But it failed yesterday and so I've now use one of my M5 units for the base.  In the process I've purchased two more M5's to replace the S4's.  I've read about power outages causing this, however both of these base units have been on a backup power unit that prevents them from going off when the power goes out. I can't reset these units once this happens either, when I try to reboot them they go from yellow to red.  I've had them for around 3 years and up to now they worked just fine.  Anyone have any ideas what's going on before I throw them in the trash?