RTK can't be recognized

QGC version 4.3.5 with CUAV C-RTK9P RTK,
Followed the official guidance setting GPS_1_CONFIG to GPS 1 and GPS_2_CONFIG to TELEM 2.
But the RTK seems can’t be recognized correctly and having no data output to QGC.
Anyone know about the reason?
Please help.

So you want to use RTK? And you have an RTK station connected to QGC that sends up RTCM corrections?

Which docs did you follow?

This one and google translated to Chinese

What’s your RTK base station? You need to have a RTK correction capable GPS (such as the ones based on the uBlox F9P) on the ground connected via USB to QGroundControl.

Thanks for the notice,
Though we had already gotten that RTK correction connected to our QGC and followed the whole instruction before we discovered this issue.
We sent the hardware to a trusted service group in China now, hoping that they could deal with it.