50MHz is too high for this reference clock. The bits RDIV can be adjusted to keep PLL input frequency in the range of 50KHz ~32MHz, which can be verified via CLKOUT pin.
MAX2769C
Production
The MAX2769C is a next-generation Global Navigation Satellite System (GNSS) receiver covering L1/E1, B1, G1 bands for GPS, Galileo, BeiDou, and GLONASS...
Datasheet
MAX2769C on Analog.com
MAX2769B
Production
The MAX2769B is a next-generation Global Navigation Satellite System (GNSS) receiver covering GPS, GLONASS, Galileo, and Compass navigation satellite systems...
Datasheet
MAX2769B on Analog.com
50MHz is too high for this reference clock. The bits RDIV can be adjusted to keep PLL input frequency in the range of 50KHz ~32MHz, which can be verified via CLKOUT pin.