Problem enabling Message Auto Archiving?

Hi,

I am facing problem enabling Message Auto Archiving.

I am using the Query :-

<iq type=‘get’ id=‘pref1’><pref xmlns=‘http://www.xmpp.org/extensions/xep-0136.html#ns’/>"

But I am getting error code=503, service unavailable

Please help me with this, any suggestion would be appreciated

T hanks

Gunjan