XFOR: Non-Delivery Report After Sending Mail To User Who Migrated From Lotus Notes

An Exchange Server user may receive a non-delivery report (NDR) after the Exchange Server user sends e-mail to other Exchange Server users who have been recently migrated from Lotus Notes. For example, if the Lotus Notes server is connected to Exchange Server site A and the Exchange Server computer that contains the new mailboxes for the migrated users is located in Exchange Server site B, the following NDR is generated:

This issue can occur if the unrecognized Common Name attribute (cn=b4501a7a-4060570b-8525644b-78c319;) is assigned to the Lotus Notes custom recipient before migration to create a unique name for the Lotus Notes custom recipient. This attribute is located in the properties for this custom recipient. Because the Lotus Notes mailbox is not migrated to the site where the custom recipient existed (in the example in the "Symptoms" section of this article, site A), but instead is migrated to a different site (site B), there are two addresses in the directory for this recipient for a brief time (the custom recipient in site A and the new Exchange Server mailbox in site B).

If the originator selects the name from the global address list, the name may resolve to the custom recipient address and then generate an NDR because the Lotus Notes mailbox no longer exists after migration. After directory replication has finished throughout the organization, the custom recipient address is removed from the global address list, which leaves only the Exchange Server mailbox address.

To resolve this issue, either wait for a directory replication cycle to finish or force a directory replication cycle.