plc cant connect to pc

[clebae infinique 0]

I am currently using 2 Mitsubishi fx3u 80m plc with a rs422 cable adaptor. The issue I am having is that I can connect to one plc but the other is giving me a error with the connection. It is only on one PLC. This the first time I am try to connect to the PLC. What is the best solution to this problem.

[clebae infinique 0]

A little more history of what is going on, I am trying to adjust some of the codes in the PLC but can't connect. The PLC is working but just can't connect to PC.

[MitsProgrammer 9]

Good day

There could be a couple of problems for not being able to communicate to your PC. 

1. Are you using a Mitsubishi RS422 adaptor? FX-USB-AW connected to the onboard RS422 serial port on the PLC?

2. If you are trying to connect through a serial adaptor or module the module needs to be setup to allow programming communication.

Please see link below for the manual for serial communication. Hope this helps.

https://www.dropbox.com/sh/dmlmfxhsslmtqwx/AACu4qvID8R83r8Q1hJne0XQa?dl=0