Sending hex command to ctouch screen on arduino with rs232

I'm trying to send a hex command from my arduino to a ctouch screen. Whenever i do this with my serial port util it responds perfectly (command i'll be sending : A9 11 00 01 8A. However when i hook up my arduino it's not responding, and I can't figure out why. If i hook up my serial port utility (on pc) to the arduino, it seems to be sending the right thing. picture of the serial port util (both sending and receiving)

sending (receiving part is ack from the tv) https://i.stack.imgur.com/s7FZI.png

receiving (from arduino) https://i.stack.imgur.com/sKEba.png

ctouch manual: https://drive.google.com/file/d/17T58Ni2ot0MjJA0tRB0rVxadoJHd41dw/view?usp=sharing my code for sending the command:

byte myHex []= {0xA9,0x11,0x00,0x1,0x8A};
mySerial.write(myHex, sizeof(myHex));

What is your "serial port util" (link to that product)? If you mean the software you used for the screenshots, post a wiring diagram that shows all components.

And post complete code, the error may be in a part that you're hiding from us.