[JDEV] Group Chat Error

[JP]

Hello,

Does anyone know what I am doing wrong  here?  I send this string to
iniciate the process to join the "jabber" group chat

<iq type="get" id="ID3" to="jabber at groups.jabber.org"><query
xmlns="jabber:iq:groupchat"/></iq>

And get back this error message

<iq type='error' id='ID3' from='jabber at groups.jabber.org'>
<query xmlns='jabber:iq:groupchat'/>
<error code='502'>Remote Server Error</error>

thanks!