Nextion Serial Communication to ESP32

I am new to programming an ESP32 with Nextion.
I am trying to make a bidirectional communication between my ESP32 board and a Nextion Enchanced screen.
I have managed to pass a data from the ESP32 board and display it on the Nextion screen, but now it is impossible to send a data from the screen to the ESP32 board.
Can anyone help me? I’ve been trying different things for several days but I don’t know what’s really wrong.

Post your code and someone may be able to help.

I am using ESP32 with Nextion. It is just UART, I don’t know what problem you can have.
You can use Debug mode in Nextion Editor and you see what data is sent via UART - and that’s what you can expect to receive in ESP32