@Toofiz 

Hi,
You can refer to the instructions below to troubleshoot if you can't control the camera in the Tapo app.
What to do if I can't control my Tapo cameras on the Tapo app?
 

Please provide the following information if the same phenomenon persists.
  1. What's the LED status on the camera, such as solid red, flashing red, etc.?
  2. What's the model number of your router? Do you have internet on your phone when connecting to the same Wi-Fi as the Tapo C510W?
  3. Try to press and hold the reset button on the camera for 10 seconds to perform a factory reset, then reconfigure it and check if it will work.
  4. If the camera still displays offline in the Tapo app, try to enable a hotspot Wi-Fi on your phone, factory reset the camera, configure it with another phone, connect it to the hotspot Wi-Fi, and then check if you can control it in the Tapo app.

Best Regards