Omemo usage failure

Hi. I’m trying to start using OMEMO encryption. The client is Miranda-NG. Here is a part of conversation between Miranda-NG and Openfire:

[12:50:14 2CC4] [JABBER_1] (ZLIB) Data sent
<iq type="set" id="mir1ecbe9dcad7401b5_942" from="user@jabber.domain.com"><pubsub xmlns="http://jabber.org/protocol/pubsub"><publish node="eu.siacs.conversations.axolotl.devicelist"><item><list xmlns="eu.siacs.conversations.axolotl"><device id="1532807079"/></list></item></publish></pubsub></iq>

[12:50:14 2CC4] [JABBER_1] (ZLIB) Data received
<iq type="error" id="mir1ecbe9dcad7401b5_942" to="user@jabber.domain.com/Office"><pubsub xmlns="http://jabber.org/protocol/pubsub"><publish node="eu.siacs.conversations.axolotl.devicelist"><item><list xmlns="eu.siacs.conversations.axolotl"><device id="1532807079"/></list></item></publish></pubsub><error code="503" type="cancel"><service-unavailable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/></error></iq>

Is that Miranda which sends incorrect request or Openfire’s issue? Please, help me to get that fixed.

PS Openfire version is 4.5.2