PL2303 Prolific Eror

Hi guys,
Iam new on red and iam trying learn to learn using node red for modbus protocol .
I want to connect it to my pc and run the flow but the problem is i found eror when i connect it to my pc
"Error: Client Not Ready To Write At State reconnecting" . It cant found the device .
By the way, the system design i want make, i want use the PL2303 Prolific connected to Innovo 1 relay using modbus communication . Do you have any suggestion for me ?
Thank you

I solve the problem using chmod 777 but i found out new problem it was said "Modbus Failure On State sending Get More About It By Logging" and "TransactionTimedOutError: Timed out".