@Tapolias 

What router do you use? If it is a mesh network, consider creating a dedicated wifi for the camera to avoid connection problems if the camera switches between different access points.

Make sure the camera is updated. How to update the firmware of the Tapo devices on the Tapo App

How long have you been using this camera? When did you notice the problems?

  @Tapolias 

Did you check the camera immediately when you received the notification? The video isn't ready if you check it too soon. If the camera stream does not load, try to open the Tapo directly next time, instead of clicking the notification. You can also restart the app: force-close it first, then re-open it.