1. "show sipue eid XXX", check the configuration of PBX
the property of "isuc" configured as "yes", so nothing wrong with PBX
2. check the IMserver configuration
Log in to the BMU as the administrator, Choose "Functions > eSpace > Maintain eSpace". check if the "IMServer service ID" and "default address" is right.
3.check the settings of AD Synchronization
Choose "Third-Party Integration > AD Integration", shows as attached picture: now the AD Synchronization has been enable, the authentication tpye configured as AD authentication. But no AD is used. So the authentication failed.
4. Disable AD synchronlization, the problem solved.