When you get an unspecified server refusal and try to diagnose the problem by running cf-serverd -v, you get no output.
this problem was fixed on master by
kacfengine authored 7 months ago (Jun 27, 2013)
Fix global log level being reset in newly created threads.
according to github.
this change needs to be backported from master to the 3.5.x branch
I've verified that libutils/logging.c from the master HEAD fixes the problem