Getting Error while create the database copy.

[Harpreet_Singh]

The seeding operation failed. Error: An error occurred while running prerequisite checks. Error: The specified database isn't configured for replication and therefore cannot be used to perform seed operations. 

[#2]

@Harpreet_Singh  Whats the current status of that database copy on that server? 

Get-MailboxDatabaseCopyStatus

Generally you can just update it to fix 

If its not suspended or throws an error that it needs to be suspended use  Suspend-MailboxDatabaseCopy

then:

Update-MailboxDatabaseCopy  <DB01\Server> -DeleteExistingFiles