New cameras won't pair

I have an HS003 Vava Cam Pro system. It has one base station and came with one camera. The system has worked fine for around a year.

I bought a second HS003 system. This one came with 2 cameras and a base station but I don’t intend to use the base station. I want to pair the 2 cameras with my existing base station so I have a total of 3 cameras on my system.

The cameras are fully charged. However when I try to add either one, pairing fails. A voice from the camera says “camera failed to sync with base station” and a message in my phone app reads “Failed to add the camera. The camera cannot be paired with a low battery. Please make sure it’s sufficiently charged before pairing.”

Again, the camera is indeed fully charged.

Other information: I am holding the camera right next to the base station when attempting to pair. The cameras are the same model and identical to the original camera. During troubleshooting I did remove the base station as a device in my app and reset it back up. It added back fine, and the original camera worked fine again after setting the base station back up - without having to even re-pair it.

How can I get these new cameras to pair?