@AlexTil
Hi,
Typically, the solid green LED on the camera means it's working. In your case, please confirm the following information.
1. Please ensure the camera is powered by the original adapter and cord, and make sure the camera is not connected to the internet via an Ethernet cable.
2. On the Tapo app, can you see the camera, and is it displayed online? Please remove the camera from the Tapo app and check if the LED on the camera will change.
3. You can power off the camera, wait for two minutes, power it on, and wait for another two minutes. Then, press and hold the reset button on the camera for 10 seconds and check if the LED changes.
4. If the LED turns to flashing red and green, you can reconfigure the camera.
Best Regards