@cs_phan 

Hi,
The solid amber light on the Tapo C210 means it's connected to the 2.4 GHz Wi-Fi network but not connected to our cloud server. In this case, you can try the following troubleshooting steps.

  1. Connect your phones or laptops to your router's 2.4 GHz Wi-Fi and ensure it has an internet connection.
  2. Try changing the DNS server on your router. Disable any special settings, such as MAC Filtering, firewall, antivirus, access control, and parental controls, on your router if they are enabled.
  3. Please try enabling a hotspot Wi-Fi on your phone, factory reset a Tapo C210 by pressing and holding the reset button for 10 seconds, configure it with another phone, connect it to the hotspot Wi-Fi, and then check if you can set it up.

Best Regards!