openfire presence plugin returns null

im trying to get the presence status of some users on my openfire server via presence plugin

http://example.com:9090/plugins/presence/status?jid=username@example.com&type=xm l

when the user is offline i get this

<presencetype="unavailable"from="username@example.com">

</presence>

but when the user is online i get nothing:

<presencefrom="username@example.com/821b0dbc"/>

anybody knows why this is happening and what could i do to resolve this?