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I'm sorry to hear that the bobbin and/or bobbin case does not turn readily. Flashing red means, most likely, that the bobbin and/or bobbin case is out of specification, or bent, and has excessive friction within the machine.
(The worse alternative is, that the motor in your machine has started to burn out, and is too weak to propel the bobbin / bobbin case. I hope that isn't how it is - the motor would be much more expensive to repair... unless your machine is covered by warranty still.)
If you have different bobbins, try swapping them in and seeing if any of them will run through.
If no bobbins will run properly, try replacing the bobbin case.
(I am presuming that you have applied routine lubrication to the machine recently, and according to the instruction manual for your machine. That is necessary now and then to keep a sewing machine in good working order.)