when glassfish starts up it tries to connect to the broker and check if it has started up. It uses the default user name/pwd guest/guest if its not configured in the jms-service. If you have removed guest user from imq then you would have to specify the user/pwd in the jms-service in the following way
<jms-service init-timeout-in-seconds="60" type="LOCAL" default-jms-host="default_JMS_host" reconnect-interval-in-seconds="5" reconnect-attempts="3" reconnect-enabled="true" addresslist-behavior="random" addresslist-iterations="3">
<jms-host name="default_JMS_host" host="IEC-AS" port="7676" admin-user-name="admin" admin-password="admin"/>
<property name="user-name" value="cps"/>
<property name="password" value="cps"/>
</jms-service>
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