Using 2 instances of rtmpdump issue

[saprizo]

Hello,
I use rtmpdump for restreaming streams from other servers to my local Wowza server using rtmpdump and ffmpeg. But I have an issue. When I try to use 2 instances ofr rtmpdump and ffmpeg start wokring only first which swiotched on first.
I already use named pipes but still rtmpdump(or ffmpeg) have some problems. I see that rtmpdump shows fetched frames for both streams but on Wowza side second stream not wokring.

What can be reason of that?