What ESCs are you using?
Are you making your connections from the fchub to F405 by the cable or by hardwiring?
Is this issue happening in Betaflight motor testing tab?
Have you tried switching ESCs to see if the problem follows?
Actually, I bought the ESC's from local market so I am attaching the photos of ESC
but when i was setting up the configuration for motor signal, none of the signal were working until I put it at the PWM signal for motor ESC
then 3 motors are working completely fine, but the 4th one is not getting any signal
I tried connecting the 4th ESC with the different port like S2 instead of S4, then that motor is working fine, that concludes that motor and ESC is fine
but the thing is it is not getting any signal in S4 port
I had used only Betaflight yet
I am soldering every joint.
Actually there are two points for connection to S1,2,3,4 ports,
Previously I had connected that point but i thought it could have been damaged so i changed the port and connected that ESC with different S4 point, which is located just below the white connection pad