Unable to set a particular refresh rate using xrandr on TegraK1

We want to output at 50Hz so when we simply xrandr it shows the possible display resolutions as well as available refresh rates. So when we select a particular resolution with 50Hz refresh rate it gives a message saying:

Rate 50.0 Hz not available for this size

Even though it is present in the available resolution with 50 Hz refresh rate.
An image is also attached to provide the better understanding of the problem.

-s is an outdated RANDR1.1 parameter relative to the output of xrandr --q1
xrandr --output HDMI-0 --mode 1280x720 --refresh 50
to set the RANDR1.2+ modes that xrandr outputs without options.