Error While configuring Database Mirroring

Hi all,
I am trying to set up Database mirroring on my test & DR server. But , I am getting the following Error: ( On local PC Mirroring is successful).
Both the test & DR have same service accounts for SQL Server.
Thanks for all your help.
Thanks. TITLE: Database Properties------------------------------ An error occurred while starting mirroring. ------------------------------ADDITIONAL INFORMATION: Alter failed for Database 'databasename'. (Microsoft.SqlServer.Smo) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=9.00.3042.00&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Alter+Database&LinkId=20476 ------------------------------ An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) ------------------------------ The server network address "TCP://Mirrorserver.domainname.local:5022" can not be reached or does not exist. Check the network address name and that the ports for the local and remote endpoints are operational. (Microsoft SQL Server, Error: 1418) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=09.00.3042&EvtSrc=MSSQLServer&EvtID=1418&LinkId=20476 ------------------------------BUTTONS: OK
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