After working for years, one of my Kasa switches started to fast blink green.  The white circle light is also fast blinking.  The KS200 switch doesn't manually operate the light.  I have a deco x55 mesh router; I rest the router and updated it's firmware.  The switch showed as being offline in the app; I subsequently deleted it.  I am trying to add it, but the switch won't reset.  All of my other switches work fine.  Any ideas?