don't get image trace

I'm assuming you actually want to work with a barcode, not just use it to test. Image trace is specifically designed to be inaccurate (which is why it can trace something with countless pixels into rather less lines), and to produce something similar according to human perception, not a barcode scanner's perception, so it is hugely unsuitable for this task.

Barcodes are simple to look at but hard to make. There are very specific rules about line widths and spacing. If you go outside these rules you will find that some barcode readers work and others reject or misread. So vectorising or otherwise editing a pattern that is meant to be a barcode is asking for a disaster. (Note also that there are very specific print size rules for most barcodes, so they have to be used with the greatest care).

It's always baffled me when I encountered people using Image Trace as part of their routine workflow. Personally, I have very little use for it. (The only thing I ever traced and then used was my signature).

You may be able to tweak some settings and get a slightly better result on that barcode, but you've already put forth a lot more effort than it would take to just generate a new barcode. Image Trace simply isn't accurate enough when precision is needed.

There's no intelligence in image trace to recognise a black box as a box. There is a tolerance setting looking at areas of contrasting pixels and drawing lines around them. Since it's trying to draw an average line, it may have problems with sharp corners or precise shapes. It's just not a good enough tool to replicate a barcode from pixels.