Weird problems with ejabberd and jggtrans

Hi,

Sorry if it's not the best place to ask for help but I have strange problem. I'm trying to migrate my jabber server from jabberd2 to ejabberd. It's the second try right now as first one failed because of jggtrans and I'm trying to sort it out now and I got stucked. I don't really know what's going on and why it keeps failing. After first try everything seemed to be fine but users reported problems they had with talking to people via gadu-gadu transport. I reproduced this problem and when I try to send something to transport itself it should return a list of all available commands or settings. On 10 tries 5 of them fail. Transport responds with an error (literally translation so could be misunderstood):

"Service unavailable.
Server or recipient doesn't share/serve requested service at the moment".

The problem is that everything is working fine with jabberd2. No errors in communication at all.

Any ideas why it happens ?

Thank you very much for your help.

Regards.

Edit:

Just tested that on a real user. I sent messages in seperate lines like numbers so 1, 2, 3 ... 15. Every single number in different line. Remote site recevied following numers: 1, 2, 3, 6, 8, 9, 10, 11, 14. So half of them are missing. Then remote site sent me the same I received all messages without any problems.