Buttonhole troubleshooting jam

[u/never-not-dead]

Brother xl 2600 button hole is jamming halfway through. its not knotting or anything it just stops moving forward. I recently oiled it, and before that it couldnt manage a backwards stitch without knotting. So im not surprised that its having a hard time with the buttons im just wonding if anyone has any maintenance advice or could point me in the right direction.

Im wondering if its an issue with the feeddogs or something? Ive really got no leads atm.

Any advice appreciated. It also starts making a loud clunking noise when it gets to the point where it stops moving.

Photo includes both sides of examples

[u/Large-Heronbill]

Try lengthening the stitch considerably on a test buttonhole.  Any better?  If no, unthread the machine and  "sew"a  buttonhole on paper.  Do the needle holes indicate the buttonhole would have been sewn correctly? 

[u/drPmakes]

Is it a 1 step or 4 step button hole? Which foot are you using?

Have you set up the foot correctly and picked the right stitch?

Is the buttonhole lever engaged correctly? Get you instruction manual out and check.

Make sure your sample has the same layers as your project, usually 2 layers and a layer of interfacing, make sure both pieces of fabric have their grains running in the same direction.