FC receiver signal problem

I have an issue with my brand new FC. It doesn't seem to process the SBUS signals from the receiver in the BF configurator. The channels are not moving on the receiver page in BF configurator when moving the sticks on the transmitter.

I have confirmed that the transmitter/receiver combo works fine with a different FC connected to BF configurator. I have tried two different UART RX ports on the FC (and configured the ports in BF configurator accordingly with the correct UART port set to Serial Rx). In the configuration menu, the receiver is set to SBUS. I have also tried CPPM from the receiver (and changed the receiver settings in BF configurator), but it didn't work either.

Other than processing the inputs from the receiver, the FC seems to work fine. I can control the motors through BF configurator and flash new BF FW. The accelerometer also works as intended.

The FC is a Diatone Mamba F405 DJI together with the Mamba F50 ESC. The transmitter/receiver combo is Radiomaster TX16S and an FrSky XSR. The setup is also tested with a different transmitter and a different receiver, but it none of those combinations work.

The wire routing and soldering is tripple checked with a second pair of (relativerly experienced) eyes.

Does anyone know what can be wrong with my FC? Are there any settings in BF configurator I might have overlooked?