Please follow these troubleshooting steps:

1. Ensure the thermostat valve is securely connected to the radiator.
2. Confirm that you are using non-rechargeable 1.5V AA batteries and that they are not low on power.
3. If you installed a valve adapter, ensure you use the stick component that came with the package, as shown in the user manual.
4. Perform a factory reset of the smart thermostat valve by pressing and holding the up and down, or + and - buttons for 5 seconds, then set it up again.