How to set up epoptes for a connection via dynamic dns ??

Unfortunatelly, it doesn't seem to work, because of a failing back route.

SERVER:
phantasy.dyndns.org

/etc/default/epoptes:
-------------------------------
PORT=789
SOCKET_GROUP=epoptes

CLIENT:

/etc/default/epoptes-client:
---------------------------------------
server=phantasy

/etc/resolvconf/resolv.conf.d/base:
-------------------------------------------------
search dyndns.org

Starting client works fine. Icon appears in Server-Gui.
But if I start a broadcast session, the following error occurs:

21/12/2014 20:44:14 Making connection to client on host phantasy port 55354
21/12/2014 20:44:14 rfbConnectToTcoAddr: failed to connect
: No route to host
21/12/2014 20:44:14 connection failed: No route to host
21/12/2014 20:44:14 connect_tcp: trying: phantasy 55354
21/12/2014 20:44:14 rfbConnectToTcoAddr: failed to connect
: No route to host
21/12/2014 20:44:14 connect_tcp: connection failed: No route to host
21/12/2014 20:44:14 connect_tcp: re-trying epoptes 55354
21/12/2014 20:44:14 rfbConnectToTcoAddr: failed to connect
: No route to host
21/12/2014 20:44:14 connect_tcp: connection failed: No route to host
21/12/2014 20:44:14 connect_tcp: trying IPv6 phantasy 55354
21/12/2014 20:44:14 connect_tcp[ipv6]: trying sock=12 fam=2 proto=6 using 176.198.xx.xx
21/12/2014 20:44:14 connect_tcp[ipv6]: connect: No route to host
21/12/2014 20:44:14 connect_tcp[ipv6]: setsockopt IPV6_V6ONLY: Protocol not available
21/12/2014 20:44:14 reverse_connect: phantasy:55354 failed