3rd Camera Will not connect

[WillowSchool]

I purchased the Arlo Pro 3 camera set from Costco.
Followed the installation instructions and very easily connected 2/3 cameras.
The third camera WILL NOT connect to the base.
Any ideas on what I can do to connect?
I did call the support line and they said it was because of my Firewall settings.  However, I told them i was able to get 2/3 cameras to connect easily.  
They were clueless.

Any suggestions?

[jguerdat]

Try pulling the battery and use only the USB power supply. Be sure to only briefly press the base sync button.  If still nothing, what does the camera LED show?

Last ditch effort would be to pull all batteries and reset the system to fresh. Remove all devices from Settings, My Devices and use the Add Device button on the Devices tab to add the base and sync the cameras.