These are things that can’t happen to everyone, no matter what level you are at.
If at any time your thread becomes a knot, it is not advisable to continue, instead of letting the needle go through the fabric, what it will do is push it inside, this will be a problem because the fabric will be buried in the machine.
If this happens, it is not advisable to pull the fabric, because this could damage the machine.
Another mistake that we can mention is sewing a slightly hard or thick fabric with a thin needle, this could be very dangerous, the needle could suffer a fracture and this will be dangerous for the person who is sewing or also for the machine, when they occur. When the needle bends, it is important to stop so that it does not break, as this would be very dangerous.