Hello,
As far as KMC is concerned, the way to debug it would be to run:
# kaltlog
as the server's shell and look at the errors outputted to STDOUT while, in parallel, launching your browser's devtools and looking at errors both in the "Network" and "Console" tabs.
As for Red5, the package comes from the distro's official repo and so, bug reports should be sent to
# aptitude show red5-server |grep Maintainer:
A good first step towards debugging it though, would be to edit /var/lib/dpkg/info/red5-serve.postinst and change the first line to read:
#!/bin/sh -x
and then run:
# dpkg-reconfigure red5-server
and look at the output.
Note that red5 is only needed if you intend to do webcam recording from the KMC.