PX4 ntrip client

I connected the RTK GNSS device to the Pixhawk thorugh the TELEM port. I use only one device. It works perfectly as a normal GPS. I have an u-center ntrip caster. I send the RTCM messages from the ntrip caster by MAVSDK to the Pixhawk.

The messaging works also perfectly. But the GNSS still don’t turn into RTK. What needs to be configured?