Something's wrong

Hello, everybody,

I’ve got X-Carve 1000 mm. For projects, I use Aspire 8.5 and UGS. In the beginning, everything’s great but then something happens, it doesn’t follow the trail. Here are the pictures.

What could be the reason? Can someone help?
Any chance it’s because of a belt?

Looks like missed steps. Check wheels, belts, and pulleys and more importantly potentiometers

Could you please be more specific? I’m a beginner.
Many thanks for your time.

What is your bit settings in aspire? Feed rate, depth of cut, plunge? By default aspire settings are too aggressive for a hobby machine.