@Leo0 

Hi,
Please check if your router has a firewall, and if yes, turn it off for a try. You can also turn off the settings such as access control, parental control, or MAC filtering on your router for a check.
If you have not tried to reset the camera and reconfigure it, please have a try.

If the problem remains, please help confirm the following information for further analysis.
1. Please send me the MAC address of the Tapo C200 via private message.
2. What's the model number of your router?
3. Please describe your network diagram in detail. For example, internet--wireless router)))Tapo C200, etc.
4. Please try to reset the C200 and reconfigure it to connect to another Wi-Fi network, such as a hotspot Wi-Fi from your phone, and then check if it can be controlled remotely after setup.

Best Regards