ejabberd worked. now it doesn't...

For some days I had my jabber server up and running.

Then it started to fail.
I did a night no error hunting, uninstalled ejabberd with apt-get purge, new install.

when I start the ejabberd process into the console, my server at jabber.mydomain.tld is reachable and I can connect. when I start it via ejabberdctl it prints:

sudo ejabberdctl start
Failed RPC connection to the node 'ejabberd@shortdomain': nodedown

my dynamic ip is set up right, I can ping shortdomain.domain.tld succesfully.
i have set up the right SRV Records.

am I missing something?

logs show no errors afaik or i don't see them yet.