Hi,

I'm using cc3d board. I have done the hardware setup using the openpilot hardware setup wizard. But during the transmitter setup wizard, openpiolot software unable to detect the rudder stick. I have done the setup for other three stick. I'm using mode 2. Also, in the display section of flysky transmitter, I can able to see the sticks are moving perfectly. How can I resolve this issue. Can any one help me.

check display option in transmitter and then move sticks and check

It works fine. I can see the display in transmitter it is perfect.

Check the connections from receiver to cc3d board.

so then the problem is in the cable.. check it

If you're using a computer radio, make sure you have programmed the rudder in the channel mixer to output on proper channel.

I use flysky th9x with cc3d ...had same kind of problem too

Everything was OK regarding tx cable and connection but till GUI didn't recognize sticks properly first time

I did it multiple times ...for 2-3 days I was very frustrated because of this problem ...
But then I did all the processes from starting ....proceed to final step slowly step by step ...and it worked ...

But my 3 position switch still not recognised by the software ....
As I remember it was only one time that software recognised my three position switch ..but I did something wrong on that attempt ...so I had to redo config ...since then it didn't recognize 3 pos switch at all

I don't know what is the problem exactly but ....search on YouTube ..a number of people complaint about the same problem ...there are few solution too on YouTube ...try them may be it would work on you ...
Best of luck
Do tell us how you resolved the problem

From the above what I understand is there is a problem with a particular type of radio /receiver. Said that, it doesn't appear to be a compatible issue because most of the channels are working. The best way to debug the issue is use some other radio and try. Note,  please pay attention to the status of the board once you connect it to your computer status needs to be orange, green, green I think(confirm on wiki).  That means you can go ahead with configuration. There is tons of info on openpilot wiki. You need to register yourself to access it.