Controller 3 not connecting

[AJE drone]

I have built my first FPV drone (should have gone BNF)
Using the speedybee F405 V3 with the 03 air unit connected to the goggles and controller 3.
I can connect the goggles to the air unit but cannot connect the controller.
In Betaflight the receiver section only shows white bars where there should be coloured ones.

I have tried flashing the firmware but have been unable to complete the process.
I have changed back to the backup firmware, but still nothing.

I have tried putting set sbus_baud_fast = on, but it returns an error about the invalid name.

Please, does anyone have idea what I have done wrong and what I can do to put it right?

[Bad Raven]

OK.

1. Flashing is an absolute last resort almost certain to give a newcomer trouble, usually as you lose the specific config the model needs.

2.  You have CLI access in Betaflight? (last option in the betaflight configurator menu

3. in CLI, enter DUMP (return), save what apppears, and post it here.

4. Also, you have bound the controller 3 to the goggles as well as the air unit? 

[AJE drone]

All sorted, turns out that the receiver on the air unit for the controller 3 in on UART 2 and not UART that it is plugged into.
Rolled back to 4.4.2 and all working just fine.
Cant take credit for sorting this out thanks to SPUD FPV from the northeast fpv facebook page.