In an Exchange 2007 or Exchange 2010 environment, the managed Active Directory endpoint acquired by Identity Manager is usually different to the Active Directory endpoints which service the Exchange 2007/2010 servers. The Active Directory intra-site or inter-site replication latency could introduce a timing problem and result in intermittent mailbox creation failures.
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To address the problem, there are 2 timeout settings which can be adjusted:
To configure Exchange 2007 and Exchange 2010 timeout settings: