I have used DMXSerial.h successfully on UNO Wifi Rev2 but need additional serial port.
My sketch does not compile when I select MEGA board and correct port.
Error message attached is meaningless to me.
Any help will be gratefully received.
I have not downloaded and looked at your error report as I wont open doc files from unknown sources but the DMX library here works on the Mega though I have not tried using it with mixed Serial/DMX ports. The only project I made with both Serial and DMX on same Arduino was for the Leonardo (32U4 MCU) that has native USB for Serial and UART for DMX.