Please troubleshoot by following these steps:

1. Ensure the thermostat valve is securely connected to the radiator.

2. Verify 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, make sure you use the stick component that came with the package, as described 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.