Hello & Welcome to Just Answer,
Sorry I didn't see your question earlier and to hear of any issue you are having with your threader.
To help you with this issue, let me send you a link to a VIDEO - that shows SEVERAL STEPS in setting up this machine, INCLUDING models that have the "auto-threader".
The information about threading using the auto-threader is at about the 7-8 minute mark of the video, but the link I have below SHOULD start the video at about the 5 minute mark - to show how it is done MANUALLY, so that you will know a bit more about how the auto-threader should work, and the thread path.
NOTE: I HIGHLY RECOMMEND that you play the video on your computer screen IN FULL SCREEN MODE, even though they do ZOOM in on the auto-threader operation.
Click here for Video --> https://youtu.be/eVXn8jUh2uA?t=303
I hope this helps. Please let me know if that works for you, or if you have any more questions.
Thanks, ***** *****