Problem with receiver side.

Hello, im using ebyte e32-DTU (433L230) with an arduino mega. The arduino on the receiver side did not receive any data. The arduino is connected to the e32 via rs232 port using only the TX,RX and ground pin. Im using your code link below. https://github.com/xreef/LoRa_E32_Series_Library/blob/master/examples/sendReceiveTransparentTransmissionMessage/sendReceiveTransparentTransmissionMessage.ino