LMX2571: Errors at particular frequency

Hello,

A customer is having problems with some frequencies, e.g. 196.05 MHz.

For reference I'm using the LMX2571EVM board connected to PC using USB2ANY module. I have set up the port TX (Set of settings F1) to the test frequency 440MHz and it works fine.

I have problems to set up frequency 196.050 MHz on the port RX (Set of settings F2). Some edit boxes e.g. VCO have red background, what does it mean? The VCO=1568.4 MHz is in the proper range 4.3-5376MHz.

1. Why do I have this warning? Can I ignore it?
2. I don't see expected tone on the port RX. How could it be fixed?
3. Could you provide settings for Fref = 40 MHz, FoutTX=440MHz and FoutRx=196.05MHz?

Thank you!

Regards,
Ryan B.