My fren's /nc not working

[AhPohPoh]

I downloaded the full installer for my fren.

I save it into the pen drive and install in his pc.

when we play, we realize the /nc not working.

I saved another copy on another pendrive and install on my other's fren pc, and the /nc works.

when i install on my pc, the /nc works too.

So how do i solve this?