@Lexi779 I'm having the same problem, though with a different light bulb type, LB120.  I've had the bulb in my home working through the Kasa app and Google Home for several years now.  About 3 days ago, one of the two LB120s I have stopped responding to commands. 

I've tried resetting the light bulb both via the three and five "turn on/off" methods and haven't had success either way.  Each time I try to add it via the Kasa app, I get to the point where the app tries to connect the bulb to the home network and then fails.  It complains that I need to be connected to the same WiFi network that I'm trying to add the bulb to.  I have been...

It looks like there are a couple other recent posts with similar issues.  I hope support actually responds.

I am having the same problem but with the KL135 light bulb. 

The lightbulb showed as disconnected in the app. After deleting it and trying numerous times to re-add it, it keeps failing during the step that should connect the lightbulb to the wifi.

@Lexi779, @gmongoose were you able to get yours working again?

  @Lexi779 I am having the same issues with K125 and unable to get it on the network. I had 2 older models that worked perfectly fine, I thought they were old so got new ones and still nothing. Has there been any help from TP-Link?

takis7 wrote

I am having the same problem but with the KL135 light bulb. 

 

The lightbulb showed as disconnected in the app. After deleting it and trying numerous times to re-add it, it keeps failing during the step that should connect the lightbulb to the wifi.

 

@Lexi779, @gmongoose were you able to get yours working again?

Follow up: 

In my case the problem was that there were too many devices (12-14 devices) connected to the one 2.4 Ghz wifi network. I created a second SSID on router, and I split up my devices to the two networks. I was then able to setup the lightbulb successfully.