Flysky FS-i6 TX/RX help

Hey all Im having a bunch of issues but ill post one at a time. my first issue is that my flysky fs-i6 transmitter shows a dead RX battery on the display (see image). Does anyone know why that is? FYI i tried switching the direct solder to other pads with same results. also used a multi-meter to check the pads on my HGLRC omnibus F4 FC and they are all outputting the same voltage. any help would be appreciated.

What voltage sensor are you using ?

Try to connect the Quad to a Battery