I have had it happen to me. This is what I do
#1--Unthread the machine completly.
#2--Take out bobbin
#3--Brush out machine or vacuum any place for lint including under the plate
#4--Oil anywhere that takes oil
#5--Put in a new needle
#6--Re thread the machine
I have discovered that most of the time with me it needs a new needle or the machine is not threaded
properly. Going through all the steps never hurts the machine.
If you go through all of the steps and you still have the problem, take the machine in for service.