It's so frustrating to have machine issues.
Did you verify that you have the correct bobbin in the machine? Is there different bobbin cases? Did you accidentally mix the Viking/Bernina bobbins?
( I have a Brother and there are different bobbin cases.)
Next, do you have pre-wound bobbins to use if available?
Do you need to plug the foot into the machine? I have to plug the WF into machine and forget to do that sometimes.
Life's to short to stitch on a naughty machine!