Mailstore replication on Exchange 2007 Seeding failed

While issuing a StorageGroupCopy on a Exchange 2007 installation to replicate a mailstore to a standby mailstore. I was faces with the following error :

Update-StorageGroupCopy -Identity EX01.yenlo.nl”First Storage Group” -StandbyMachine EX02.yenlo.nl

[PS] C:Windowssystem32>Update-StorageGroupCopy -Identity EX01.yenlo.nl"First
Storage Group" -StandbyMachine EX02.yenlo.nl -DeleteExistingFiles
WARNING: Replication for storage group 'EX01First Storage Group' is still
suspended. If needed, you can use the Resume-StorageGroupCopy cmdlet in the
Exchange Management Shell to resume replication.
Update-StorageGroupCopy : Seeding failed : Database seeding error: Error return
ed from an ESE function call (0xc7ff1004), error code (0x0).
At line:1 char:24
+ Update-StorageGroupCopy <<<< -Identity EX01.yenlo.nl"First Storage Group"
-StandbyMachine EX02.yenlo.nl -DeleteExistingFiles
+ CategoryInfo : InvalidOperation: (EX01.yenlo.nlFirst Storage
Group:StorageGroupIdParameter) [Update-StorageGroupCopy], ErrorOnlineEdbSe
edingException
+ FullyQualifiedErrorId : 75A78D04,Microsoft.Exchange.Management.SystemCon
figurationTasks.UpdateStorageGroupCopy


As it turned out , this error was due the fact that a connection
was blocked by the firewall on the other side.

To overcome this , i added the Windows PowerShell to the
firewall exceptions.