If you're not using yet, consider using the SQLServerDataSource to set your server configurations. Also, check if the server is accepting TCP/IP connections and if there's no firewall blocking the connections.
You have a different solution? A short tip here would help you and many other users who saw this issue last week.
- com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed.chainedExceptionMessage:The connection is closed. chainedException trace:com.microsoft.sqlserver.jdbc.SQLServerException: The connection is closed. at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(Unknown Source) at com.microsoft.sqlserver.jdbc.SQLServerConnection.checkClosed(Unknown Source) at com.microsoft.sqlserver.jdbc.SQLServerConnection.prepareStatement(Unknown Source)