Check the cable is fitted correctly - connector on the end near the twist in the cable to the floppy - connector at the other end to the motherboard (do not use the middle connector).
It's vital that pin1 on the cable goes to pin1 on the connector at both ends.
It could be a faulty cable.
Check the BIOS is set to the correct type of floppy drive 3.5" 1.44 Mb
It may be a faulty motherboard.