Small Appliance Repair Questions? Ask a Technician ASAP
Hi, thank you for contacting JustAnswer.com. My name is***** will do my best to provide the right answer to your question.That message probably means that the lever, sensor switch, or even circuitry, that senses the bobbin thread level, is defective somehow.
First thing of course is to take out that bobbin, see if the 'lever' that presumably senses the bobbin thread amount wound on the spool, is still there, or broken off, or not engaging, or the spring that drives it is - doubtfully - broken or disengaged, etc. etc. See what you can see, there.