Have you ever tried to use the Copy Database Wizard? It is a handy tool, but troubleshooting it takes more time to do than just manually copying the database yourself. If you do try to troubleshoot, then most likely you will see this error in default setups.
StackTrace: at Microsoft.SqlServer.Management.Common.ConnectionManager.Connect()
at Microsoft.SqlServer.Dts.Tasks.TransferObjectsTask.TransferObjectsTask.OpenConnection(Server& server, ServerProperty serverProp)
InnerException-->Login failed for user
On an Event ID 12550 on the source server. It is basically telling you that the account you used does not have permission to do the actions. By default the wizard will want you to use the SQL Server Agent account. That will need permissions to create files in the log and data directories. It will also need permission to import the database files in SQL