Multiple IP's - no such HOST

Hi,
I have a really nasty problem configuring SIP gateway, I tried everything pls help.

ERROR:


Apr 10 13:11:49 WARNING[30266]: chan_sip.c:1973 create_addr: No such host: sip.sparvoip.de
Destroying call '69bb43810815958b1c09228e0582a640@194.213.226.203’
Apr 10 13:11:49 NOTICE[30266]: app_dial.c:1012 dial_exec_full: Unable to create channel of type ‘SIP’ (cause 3 - No route to destination)

I noticed that DNS of sparviop.de resolves to 5 different IP’s with different priorities - if I connect via IP not “hostname” and I choose IP with highest pririty it is OK, but after some time it goeswrong as IP changes. I would like to use domain name but it does not work at all!

I read that asterisk has very simplivied DNS lookup is that true? is this the problem?

pls help
regards
Kuba