The F8 error on a Brother embroidery machine typically indicates a problem with the machine’s motor. Here are some steps you can take to fix the issue:

1. Turn off the machine. Turn off the machine and unplug it from the power source.
2. Check the motor. Check the motor to make sure it is not damaged or blocked. Check for any debris or thread that may be caught in the motor.
3. Check the belts. Check the belts that connect the motor to the embroidery arm to make sure they are not damaged or worn.
4. Check the embroidery arm. Check the embroidery arm to make sure it is moving smoothly and is not blocked or jammed.
5. Restart the machine. Once you have checked these components, plug the machine back in and turn it on again to see if the F8 error has been resolved.

If these steps do not solve the F8 error, it may indicate a more serious problem with the machine’s internal components. In this case, it is best to contact a qualified technician or the manufacturer for assistance.