THE uart of 52832

When I used  "nRF5_SDK_15.0.0_a53641a\examples\ble_central\ble_app_uart_c " ,  it run ok .    But my hareware  is used  PIN33 for RX,  PIN32 for TX. So I  changed  pca10040.h ,please see the following .  And now the software doesn't  run. The J-LINK shows  "  0> <error> app: Communication error occurred while handling UART. ".

WHY? please help me. thank you.  My board is uesd 52832.

#define RX_PIN_NUMBER 19  / /8
#define TX_PIN_NUMBER 18  //6