Unable to get the output birate in Zixi

Hi Team,
I am streaming to the rtmp url and the same rtmp url I am pulling into zixi to publish it on another server, but I am getting bitrate as 0 in zixi. I have tried so many configurations but still I am getting the 0 bitrate in zixi.

rtmp://sai.xyz.net/xuv/sai999 -format flv -vcodec libopenh264 -b:v 6000k -crf 0 -tune zerolatency -preset ultrafast -acodec acc -ar 44100.

I am using the above configuration for rtmp streaming. Please suggest how to get the bitrate in Zixi when I am pushing the feed to any RTMP/UDP?