Check the device's battery level in the App. Charge it up if it is too low. Remember, the battery inside might be dead if you did not charge it for quite a long time when the battery is too low.
If you recently relocated your device, try to move the camera closer to the router, or AP. Alternatively, you can add a Wi-Fi extender between the device and the router.
If you recently relocated your AP or routers. Try to move them back to their original places.
Try to set it up again, then update it to the latest firmware.
If the above steps cannot solve the problem, feel free to contact us via firstname.lastname@example.org.