Hi there,
Yes. 
I bet it doesn’t work in the App then?
HTH
GL 
PJ 
baud_rate: 115200
rx_pin: 17 (no such pin no,) C3 it’s GPIO4 & GPIO5 , C6 its GPIO02(RX) & GPIO21(TX)
tx_pin: 16 (nope)
parity: NONE
stop_bits: 1
FYI, Those pins are for the DeV-KIT 1C hardware, you are using a Xiao.