Development Guide for Unified Communications Managed API version 1.0

Hi There is a problem.we depolyment ocs2007 enterprise.I develop a program IM bot using ucma v1.0.follow is the question:
1).When I start my IM bot.I can register the endpoint and send message ok.But other side using communicator send message to me error with ID:504. I means I can send but not receive message.How fix the ID:504 error?
2).But I using the same IM bot program starting in the ocs2007 standard .There is no any error appeared.I means not only send message successful but also receive message successful.I want to konw there is a mistake whether is my deployment ocs 2007 enterprise problem or is the ucma v1.0 API problem.

Who can tell me,I am trubled by half a month.
you also can email me.my email address is : leoliuqixing@gmail.com.
Thanks for your help.