Dang or darning foot
 

I am a little ashamed to be posting this, I have been sewing and quilting for a very long time and quiet a few quilts under my belt. My sewing machines range from very old to very new, 10 total. They all sew very well.
Now to show how stupid I really am, here is my question.
When I put the darning foot on any of my sewing machines, they forget how to sew! ( can't be me!) The needle goes down but only picks up the bobbin thread once in awhile, maybe once out of 10 or 20 stitches! I put the feed dogs down or cover them. I tried 3 different hopping or darning feet and they all work the same. What the heck? I'm at my wits end. I have a lot of Christmas quilting and sewing.
I do have one machine that will sew with the darning foot, it is a Singer Futura 250 Embroidery machine. But the harp space is too small to do any real quilting.
Can anyone please help? And yes I did re-thread the machine, many many times.
I can't help to feel so stupid!

Are you putting down the presser foot? Even my darning feet require me to use the lever in the back to put the foot down towards the fabric.

Did you put the presser foot down. That is my most common mistake, waaaay too often.

Besides putting the presser foot down. When you put the darning foot on to the shaft, there is a little "finger" piece that needs to rest on top of the needle screw. Sometimes that doesn't happen. :o)

Somemschines have the presser foot go partially dowm ( my pfaff 1471) - my old bernina (1962 vintage) also needs to lower the feed dogs and lower the presser foog.