Error when registering device

[jwangga]

Hello,
I am running backend and frontend locally on the same machine. When I tried to add a new device (device/new), I got several errors related to
SyntaxError: Unexpected token < in JSON at position 0
And the error 500 (Internal Server Error), which seems to cause the QR not to display
GET http://localhost:58600/api/devices/qrcode?nonce=a605b457-0d68-8b96-bb99-70b155131268 500 (Internal Server Error)

What could be the cause? Any suggestions would be greatly appreciated.

jwang