As my scan for open/closed/filtered ports shows, all the neccesary ports are in fact reachable.
Version 5.1 (without pachtes) does also work. The infrastructure is a VPN where I have access to all ports I need.
another strange thing is, that this strange phenomenon appeared after some time.
the one host after about 100 hours (6000 minutes, 360000 seconds) the other one after about 152 hours.
