I recently added a TP-Link Tapo P110M smart plug to Home Assistant. The plug worked normally in the Tapo app, but Home Assistant refused to connect and displayed:
Connection error: Device responded with 403 to handshake1
Home Assistant then asked for my TP-Link cloud username and password. Entering the correct account details did not help.
The fix was simple: I turned Tapo’s Third-Party Compatibility setting off, waited briefly, and turned it back on. Home Assistant connected immediately afterward.
The quick fix
In the Tapo app:
- Tap Me.
- Open Third-Party Services.
- Select Third-Party Compatibility.
- Turn Third-Party Compatibility off.
- Wait about 10 seconds.
- Turn it back on.
- Return to Home Assistant and try adding the P110M again.
When Home Assistant asks for authentication, enter:
- your full TP-Link account email address; and
- your TP-Link/Tapo account password.
These are the credentials for the same account used in the Tapo app. Do not enter your Wi-Fi password.
Why enabling the setting may not be enough
In my case, Third-Party Compatibility appeared to be enabled already. Home Assistant still received a 403 response during the first connection handshake.
Turning the setting off and back on appears to refresh or re-authorise third-party access for the account or newly added device. I cannot confirm exactly what Tapo changes behind the scenes, but the toggle—not simply re-entering the same credentials—resolved the error on my P110M.
This is worth trying when:
- you have just added a new Tapo device;
- existing Tapo devices work but a new one does not;
- the plug has recently received a firmware update; or
- Home Assistant repeatedly rejects credentials that work in the Tapo app.
Check these basics first
Before changing the compatibility setting, make sure the P110M is:
- fully configured in the Tapo app;
- connected to your home Wi-Fi;
- online and controllable from the Tapo app; and
- reachable from the same local network as Home Assistant.
Also check that you are using the TP-Link account email and password associated with the device. Enter them exactly as registered.
If the plug still will not connect
Try this sequence:
- Toggle Third-Party Compatibility off and on again.
- Unplug the P110M for about 15 seconds.
- Plug it back in and wait until it reconnects in the Tapo app.
- In Home Assistant, reload the TP-Link integration.
- Try adding the plug again.
To reload the integration, go to:
Settings → Devices & services → TP-Link Smart Home → Reload
If it still fails, restart Home Assistant and retry after the restart has completed.
A factory reset should be the last resort. It removes the plug’s existing setup, so you will need to add it to the Tapo app and configure it again before returning to Home Assistant.
What fixed mine
The P110M itself was online, the account credentials were correct, and the plug worked in the Tapo app. Home Assistant continued to report 403 to handshake1 until I cycled Third-Party Compatibility off and on.
After that refresh, Home Assistant accepted the same TP-Link account email and password and connected to the plug immediately.
Menu names can change between Tapo app releases, but the setting to look for is Third-Party Compatibility under Me → Third-Party Services.