What bobbins are you using in the machine? You might try the pre-wound for your machine. Re-check that you are using the correct size bobbin. I only use the bobbin brand for my machine and not universal ones.
My embroidery machine has two different bobbin cases. I had to change to the other case and no more issues. It had something to do with the set screw being fixed in one bobbin and adjustable in the other bobbin.
What needle size and type are you using? I think there are brand specific needles for your machine. I use Schmetz Micro-tex 80/12 for most of my EMB and sewing projects. Be sure the needle is inserted all the way UP into position.
What type of stabilizer are you using? What type of project? What design?
Does the machine work with other designs or sewing (if a combo machine)?
What thread are you using? Are you hooping the project or floating ITH? Does this happen with different brands of thread?