TP-Link Kasa Can't Connect During Setup — How to Fix It

What it means

When Kasa setup fails — stuck on 'Connecting', 'Couldn't connect to your device', or 'Failed to add device' — it's almost always Wi-Fi.
Kasa devices only work on the 2.4 GHz band, and modern routers often hide 2.4 GHz behind a single combined network name, so your phone hands the device 5 GHz details it can't use.
The other usual cause is a mistyped Wi-Fi password.
It's a setup-stage problem, not a faulty device.

Affected Models

Kasa Smart Plugs (HS103, HS105, KP115, KP125, EP10, EP25, power strips)
Kasa Smart Light Switches and Dimmers (HS200, HS220, KS200M, etc.)
Kasa Smart Bulbs (KL110, KL130, KL135, etc.)
Kasa Smart Cameras (KC100, KC200, EC60, etc.)

Common Causes

Phone on a 5 GHz network — Kasa devices only use 2.4 GHz
Router combining both bands under one name, so the device gets 5 GHz settings
Wi-Fi password entered wrong (it's case-sensitive)
Device not in setup mode — needs a factory reset if it was set up before
Phone too far from the device, or 'AP isolation' / guest network blocking device-to-device setup
Special characters in the Wi-Fi name or password the device dislikes
VPN active on the phone during setup
Outdated Kasa app

How to Fix It

Put your phone on 2.4 GHz Wi-Fi.

Connect your phone to the 2.4 GHz network for setup.
If your router uses one combined name for both bands, log into the router and either split them into separate names temporarily, or enable the 'Smart Connect off' / IoT-network option so a 2.4 GHz-only device can join.
Turn off any VPN on the phone.
Factory reset the device, then start over.

If the device was set up before, it isn't listening for setup — reset it.
For most Kasa plugs/switches/bulbs: press and hold the button for about 5–10 seconds until the LED blinks rapidly (amber/green).
Then in the Kasa app, add the device again from scratch.
Re-enter the Wi-Fi password carefully.

The password is case-sensitive and one wrong character fails setup without explaining why.
Type it slowly, watch for an auto-capitalised first letter, and don't paste if your keyboard might add a trailing space.
Keep the phone, the device, and the router fairly close together while setting up.
Turn off guest mode and AP isolation.

In your router's settings, make sure you're not connecting through a guest network and that 'AP isolation' or 'client isolation' is off — those stop your phone and the Kasa device from seeing each other during setup.
Update the Kasa app to the latest version too.
Try a phone hotspot as a test.

Create a 2.4 GHz hotspot on a second phone, connect your main phone to it, and run Kasa setup on that.
If the device adds successfully on the hotspot, the problem is your home router's settings (band, isolation, special characters), not the device — adjust those and try again.

Frequently Asked Questions

How do I get my Kasa device onto 2.4 GHz when my router uses one network name?

Log into your router's admin page and look for the wireless settings.
You can usually either turn off 'Smart Connect' / 'band steering' so the 2.4 GHz and 5 GHz networks get separate names, or create a dedicated 2.4 GHz 'IoT' network just for smart-home gadgets.
Connect your phone to the 2.4 GHz name, run Kasa setup, and once the device is added you can leave the networks however you like — the Kasa device will stay on 2.4 GHz.