If you change to a new wifi, wifi extender or new password, you need to reset and re-add the camera.
You could check the connect steps in the videos in this link, reset the camera and add it again.
https://www.zumimall.com/blogs/news/how-to-reset-and-connect-the-camera-new
Please note that some of the camera models supports only 2.4GHz WiFi. They do not support 5GHz WiFi or Mesh WiFi systems.
If still not work, pls email to the customer service.
Email: support@zumimall.com