I've recently bought a cnc3018 pro from amazon to learn about nc and have a little fun.

The machine came with an offline controller which works fine with the example files that came on the SD card. But if I create gcode using Easel, download it my laptop and copy the file onto the SD card, the contoller sees the file but the machine does not do anything when I try to run it. The controller then doesn't respond and I have to switch the machine off and on again. Any ideas what could be going wrong?

I would like to persevere with the offline controller to be independent off laptop position

Many thanks