Error: SMTP Resolver is not set or unable to find record for (4315280)

Issue
You may encounter the error SMTP Resolver is not set or unable to find the record for during a migration from Source One archive manager.

See the example below:

 2018-05-21 08:05:48Z|3644|S1 server| 17|ERROR| SaveItems|Item export failed! Item Identifier: [201610%20161031231201%59B81084231068419C7EEDB763E602BE12B31234567890], Bucket Id: [-3515994502517958093], Mapping Id: [1492], Routing Id: [27738950]. Error msg: System.InvalidOperationException: SMTP Resolver is not set or unable to find record for [/o=John Graham/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Aidan Loughrey8e0]. Unable to set journal P1 sender! at Timefinity.ConnectorFramework.SourceOne.SourceOneJournalReconstructor.SetValidSenderAddress(Message message, IJournalEnvelope envelope)
 at Timefinity.ConnectorFramework.SourceOne.SourceOneJournalReconstructor.CreateEnvelope(Message message, IList`1 databaseRecipients)
 at Timefinity.ConnectorFramework.SourceOne.SourceOneConnector.ExtractItems[T](String bucketId, IList`1 itemIds, Nullable`1 messageSizeLimit)

Solution
During the reconstruction of P1 journal message header, Archive Shuttle is trying to reconstruct the sender SMTP address. In some cases, Archive Shuttle is trying to fetch the SMTP address from the LegacyMailboxDN record. If Archive Shuttle doesn’t have any records about users in Archive Shuttle database, then error above is logged.
Each target system has requirements for the ingestion of a message. If the message in the source does not contain the properties to meet these requirements, importing those messages fails .​​​