[jitsi-users] invite others "conference is being created" - nothing is created

I installed jitsimeet according to the "detailed installation" and "quick-install" at github on Debian Wheezy x64 (two separate VMs; static IP and internal DNS record set) but I always get the invite window telling me "conference is being created" but nothing ever happens. Browser is Chrome v40x. I have tried https://meet.jitsi.org/ and https://meet.jit.si/ with the same symptoms.
I must have missed something - or what and where can I start debugging?
Thank you