@WhiteRoseAl 

Hi, 
For the reported phenomenon, please confirm the following information for analysis.

  1. What's the model number of the SD card inserted into the camera? Please refer to the instructions below to test the SD card with the third-party tool "H2testw", then send us a screenshot of the test result.
      How to Verify Fake Micro SD Cards

  2. How many KC420WS do you have?

  3. On the Tapo app > camera's Device Settings > Storage & Recording > Local Storage page, can you see the Loop Recording option? Is it enabled?

  4. Can you see the Reboot Camera feature at the bottom of the camera's Device Settings page? Can you control the camera remotely via the Tapo app? For example, when your phone uses mobile data to go to the internet, does the KC420WS display online in the Tapo app?

  5. What's the model number and OS version of your phone? What's the Tapo app version?

Best Regards
 

  @WhiteRoseAl 

Hi,
1. Please click "microSD Card" on the camera's Storage & Recording page, then check if the Loop Recording feature is enabled.

2. According to the KC420WS's UG, it should be the camera does not have the Reboot feature, so you can't see this feature in the Kasa or Tapo app. 
 

3. Whether the reported phenomenon starts occurring after updating the Tapo app to v3.15.112?

You can uninstall the Tapo app on your phone, copy this link, paste it into your phone's browser to download and install the Tapo Trial app(v3.15.117), then test whether this resolves the reported phenomenon.
 

Note: You can refer to the instructions below to see the "Compatibility List of microSD Cards We've Tested", and the Sandisk Ultra 256GB SD card is not on the list.
What type of microSD card does Tapo/Kasa Camera support?
 

Best Regards