Can not interface with Insteon PLM

OK. been doing some on line research since there doesn’t seem to be any real instruction on this. (I know open source). I found this discussion [Insteon PLM configuration/startup issues]. which seemed to infer that editing configurationY,AML was best approach to this. I tried with this.

insteon

insteon:
port: /dev/tty.usbserial-A906XKU0

No joy. I get this error.

  > 2021-11-19 10:55:08 WARNING (MainThread) [pyinsteon.protocol.serial_transport] Unable to connect to /dev/tty.usbserial-A906XKU0: [Errno 2] could not open port /dev/tty.usbserial-A906XKU0: [Errno 2] No such file or directory: '/dev/tty.usbserial-A906XKU0'

I am stumped. I have tried the UI hand editing. As seen above the device path APPEARS correct. Any comment thoughts or brainstorms would be appreciated. I have good number of insteon devices.