Modbus Slave Set error

[seokgi]

Hello?
I would like to inquire because the initialization failed while working on a project.

MCU: PIC18F45K40
Component: MODBUS SLAVE
Modbus slave 1: RC7(RX) RC6(TX) RC0(DIR)
Modbus slave 2: RB7(RX) RB6(TX) RC1(DIR)

Modbus slave uses channels 1 and 2 as slaves.
Modbus Slave 2 is set up well. However, Modbus slave 1 is not set and RC6 and 7 are changed to RD Port.
Is there any way to solve this?
Thank you.