I am trying to add a Matter device (Aqara Door and Window Sensor P2) to my SmartThings system (hub v2, firmware 000.048.00005) using an external Thread Border Router.
From the SmartThings Android App, I try to add a Matter device and scan the QR code. I select my Eero Thread network and enter the Network Key copied from my Eero App. It spins a while (Registering your device) but eventually fails with
Something went wrong. Try again later.
Error code: 39-513
The SmartThings App also finds/offers my Google Home system’s Thread network but I have no idea where to find its Network key.