Arduino Board Uploading

Hi guys, i have a Arduino nano board and when I connect the same with the PCB board, I am getting the error like " Problem uploading the sketch " or " The board does not exist ". When I remove the Arduino nano from the PCB board, I can upload my code successfully.
What will be the issue?
Can anyone help me?

In one of the computer, this arduino code is uploading with PCB board. But in computers/laptops, It is not uploading.
This is the schematic design :

Metal Width Detector.pdf (168.9 KB)

This will usually indicate that you're using pins 0 and 1.
But the below would contradict that and is confirmed by the schematic.

Can you please insert an image in a post instead of attaching a pdf.

Are you using the same pcb and Nano for tests with the different computers?