For your reference, here are some troubleshooting steps:
1. Make sure the camera's lens is clean and dust-free, sometimes, smudges or dirt on the camera lens can cause blurry images. Use a soft cloth to gently clean the lens of the camera to ensure clarity;
2. Ensure that the camera is properly positioned and focused. Adjust the angle and direction of the camera to see if it improves the image quality during night vision mode;
3. Check whether the lens is blocked by sundries, if so, rotate the PTZ or move the camera position in the Mi Home/Xiaomi Home APP to move the lens out of the blocked area;
4. Ensure that there is sufficient ambient light for the camera's night vision mode to operate effectively. Night vision cameras require some level of infrared (IR) illumination to capture clear images in low-light conditions. If the area is too dark, the camera will struggle to produce clear images.
We hope the above methods can help you solve the problem. If your problem still exists, please contact the local after-sales service center for further assistance.