In the eventviewer on an Exchange 2013 you might notice an error being reported every 60 seconds with Event ID 1121, MSExchange Replication Service.
Log Name: Application
Source: MSExchange Mailbox Replication
Date: 26-9-2017 11:43:14
Event ID: 1121
Task Category: Request
The Microsoft Exchange Mailbox Replication service was unable to process a request due to an unexpected error.
Request GUID: '4c037387-462c-446f-855d-1a4a9f4769bc'
Database GUID: 'f76ac2d8-bf20-4646-88a1-5f9161f5f312'
Error: Database 'f5c17f94-0b61-472e-9908-048b145e740c' doesn't exist..
Check if there are any open mailbox move requests, export requests, import requests of migration batches. If there are any open requests remove or complete these if there are no …
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