Chime will not install

I have a Ring doorbell, 2 cameras and 2 chimes (latest version), connected via an iphone 14. One chime works fine, the 2nd chime disconnected and I simply cannot reconnect. I have tried with 2 replacement chimes, including plugging it in directly next to the 1st functioning chime, but the installation process always concludes with a red flashing light. It can’t be the hardware since I have now tried with 3 different chimes, nor the network since the system works fine with everything else… Can anyone suggest how to fix this??