Pidgin & OpenFire
Openfire (aka WildFire) a very well known jabber server won’t work with Pidgin, a famous IM client, because of a lack of support by Java in RFC 2831implementation, as you can also read here, here and here.
Before giving up digging inside Openfire awkward documentation and obscure groups suggestions just pick up you openfire.xml file in /opt/openfire/conf and add, just before closing </jive> elements, these few sentences:
<sasl>
<mechs>PLAIN</mechs>
</sasl>
They’ll do the job.