unable to add storage on rpi-monitor

[boomramada]

I'm try to add a storage on rpi-monitor with following config

static.10.name=storage1_total static.10.source=df /dev/sdc1 static.10.regexp=\S+\s+(\d+).*/$ static.10.postprocess=$1/1024

But I'm getting following error

but when I run df /dev/sdc1, this is the output im getting

Filesystem 1K-blocks Used Available Use% Mounted on /dev/sdc1 125041660 51140168 73901492 41% /media/temp

which should pass the \S+\s+(\d+).*/ any Idea why its not working?