Nest Camera Battery cannot connect through phone bluetooth

[VinOng]

I have just replaced the Internet Modem, which automatically changed the Wifi Connection.  I can change the Wifi connection on the Google Hub Display but not on the two Cameras. 

I followed online advice to delete the Cameras (Battery type) from the Home App and then add them back for setup with new Wifi.  Whatever I tried, the Cameras will not connect to the Phone Bluetooth with Camera Setup Codes.  I used the Camera Setup Codes (from the back of the Camera), because I do not have the Camera Barcodes.  I have performed the followings without any success:

1. Closed the Home App and Restart the App (A few Times).
2. Disabled the Bluetooth for at least a minutes then enable the phone Bluetooth (A few times).
3. Restarted the Android Phone (Samsung Galaxy 10+) a few times.
4. Reset both Cameras to default and repeat step 1 to 3.
5. Used Iphone 10 and go through the same process from step 1 to 2.
6. Swapped to a different Camera a few times.
7. Phone was resting on the Camera or within 100mm from the Camera during the attempt for Bluetooth connection.

How can this issue can be resolved:

• Cameras have reset to factory default hence it should not look for old Wifi Connection?
• What is the possible way to reconnect to the Cameras so they can be configured to connect to the new Wifi?

[MplsCustomer]

@VinOng 

I can't tell from your post whether you performed a factory reset on your battery camera (to clear the old Wi-Fi settings).

Press and hold the reset button on the back of the camera head.

At 10 seconds, the status light will blink yellow four times, and you'll hear a countdown tone.

At 12 seconds, the status light will be steady, solid yellow while the camera starts the factory reset, and you'll hear a confirmation tone.

Release the button. Your camera will restore to its factory settings.

https://support.google.com/googlenest/answer/9252162