RS485 Comms Cape A2

I am writing to you because I have a problem with the RS485 communication.
I’m using the “Beaglebone Comms Cape A2”.
I use UART4 port (/dev/ttyS4)
I configured PIN 13 and 11 as UART and all serial parameters are correct.
I also use the latest version of the board firmware.
The problem is that I can only send data correctly but I don’t receive anything. Can you suggest me a solution? Thank you