@Lawrence01 

Boot the camera up, then once the LED starts going amber/green, hold the reset button for 20 seconds. This will do a full reset rather than just resetting the Wi-Fi settings.

Verify the wireless password you are putting into the Kasa app is the correct one, by forgetting the Wi-Fi network on your smartphone, then connecting back. When prompted to enter the wireless password, use the same one you used when setting up the Kasa app.