Cameras work fine only few days

I have problem with my eufycam 2c, after installation every thing is ok, but after few days I cannot connect to the cameras. Motion detection not working. Home base is busy.

To back to the normal state I have to remove all cameras, reset system to default settings. Connect cameras to base again etc. After that cameras works fine, but only few days.
What is the core problem? What I can do to have fully working system?