@Rikard_Tordon 

Hello, 

Sorry for the inconvenience caused there, we can try to do some troubleshooting to fix the issue.

When the devices gray out on the app, if you click on them, is there any error message? Such as Device Unreachable.

What's the light status on the device?

Do you have any special settings on the router? Such as AP isolation or SSID isolation? In theory, your phone and devices can be in different networks. 

Please try to log in to your account on another phone or iPad, if you are still not able to control them there, please factory reset the devices and reinstall them. You can also reinstall the app on the phone. The way to factory reset as below.

https://www.tp-link.com/support/faq/2660/

https://www.tp-link.com/support/faq/2648/

After that, please help to confirm the information below.

1. The model number, hardware version and firmware version of the devices. 

2. The app version. 

3. The device's signal strength (in device info page).

4. Your phone's model number&system version.

5. When did you buy the devices and when did the issue happen?

@Stella.Q 

OK. Thank You for helping me. Actually, the app have started to work again. I turned the power off to all my devices for some minutes, and then on again after a couple of minutes to give them a fresh router connection. It worked!

But for future reference, here are the answer to your questions:

When I clicked on the greyed-out devices, I got the message "the device is off or out of network range" or something similar.

The light status (in the app) was off, my smart plugs led indicated red (no connection to wifi) and the light bulbs were either off if that was their status when the Kasa system halted, or on to last known brightness. 

No special setting on the Router, (Technicolor TG799vac, from the Swedish network operator TELIA).

The same greyed-out view meet me on every other phone (Samsung S8, S7 and the tablet Samsung Tab A (2016))

1, 3. The Smart bulbs:

One LB120, HW 1.0, FW 1.8.11, Signal strenghth: -65 dBm

Three LB100, HW 1.0, FW 1.8.11, Signal strength: -77, -72, -63 dBm

The Smart plugs:

Three HS100, HW 2.0, FW 1.5.4, Signal strength: -54, -49, -57 dBm

2. App version 2.19.0 Build 911

4. Phone: Samsung Galaxy S8 SM-G950F

5. Between 2018 and 2020, intermittent problem with increased frequency from first month of use.

@Rikard_Tordon 

Thanks for the details.

The devices gray out on the app because they lose the connection to the router. The firmware version of them is the latest, but the signal strength is not good enough. -40~-50dBm represents a very good signal, -70~-80dBm means weak signal and that connection may drop. To get a favorable experience, we suggest placing the product where its signal strength is between -40~-70dBm. If the signal strength is about -60dBm when the product is right next to the router, then it’s better to check the router’s Wi-Fi settings.

You can try to move the devices closer to the router, or optimize the router's wireless settings, such as change the channel to 1,6 or 11, change the bandwidth to 20Mhz.

@Stella.Q 

Thanks!

Now when I learned about signal strengths, I plugged in a wifi range extender close to the devices with the weakest signal. Better now. Moving devices is not an option, lights are there for a reason ;-)

Rikard

@Rikard_Tordon 

Hi Rikard,

You are welcome. Glad to hear they are better now:)

If need any further help, just let us know.

Good day.

@Rikard_Tordon Hi.  I've got ten bulbs and nine plugs, the bulbs lose connection frequently and the only way to get them back is to turn them off, wait for three seconds and turn them back on again.  The plugs are better but occasionally one will lose connection.  I installed a TP-Link range extender and it didn't help at all.

I'm trying a new tactic which is to remove a particular problem bulb from its bayonet type light fitting, rotate it 180 degrees before refitting it to see if that helps; the idea is that the bulb might receive a better signal having been rotated.

Like you I've invested too much money to ditch them and start again with another brand.

Regards.

Nigel.

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