Option boards in slots A, B, and C would not be cause of this fault since they only provide such functions as additional input/output terminals, communications, and encoder feedback interface for drive operation.
For your drive part number 6SE7021-3TP70, specifically need to check supply voltage for drive to identify where problem starts. See attachment from hardware manual where DC link is present at top of drive under protective cover. When looking at drive with cover open:
Bar 3 is in back PE3 Protective conductor connection
Bar 2 is in middle DC link voltage -
Bar 1 is in front DC link voltage +
Assuming the AC input supply voltage is 415 VAC Three Phase, then DC voltage to the drive should be approximately 415 * 1.35 = 560 VDC.
If dc voltage across the DC terminals of the drive with voltmeter is not approximately 560 VDC, then the fault is caused by issue somewhere in incoming supply upstream of individual drive (i.e. rectifier, contactor, AC input supply fuse, circuit breaker, etc.)
If you measure the dc voltage across the DC terminals of the drive with a voltmeter the voltage is also as per the specification (approx 560V dc) but still the drive trips with this F002 fault. You have to now check the value of r006 and compare it with what your voltmeter reading at the same instance. If the values do not match ( you will find the value of r006 is 0v or very much lower than the actual voltage measure by the voltmeter) the drive will trip with F002. What happens here is the actual dc voltage is correct but the DC measuring circuit is not measuring the voltage correctly and the microcontroller feels that the required voltage is not reached and trips the drive with F002.
This would indicate that the 6SE7021-3TP70 drive itself needs to either be repaired or replaced as there is not a spare part sold seperately for field exchange to attempt repair.