JDBC Data Source Fails to Connect to the Database With Error: The Network Adapter could not establish the connectionIssue You do a Load or Test Load of records from a JDBC data source, it fails with this stack:MID Server reported error: java.sql.SQLException: java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connectionoracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:458)oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:546)oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:236)oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)java.sql.DriverManager.getConnection(DriverManager.java:664)java.sql.DriverManager.getConnection(DriverManager.java:208)com.service_now.mid.connections.jdbc.JDBCConnection.establishConnection(JDBCConnection.java:110)com.service_now.mid.connections.jdbc.JDBCConnection.connect(JDBCConnection.java:82)com.service_now.mid.connections.jdbc.JDBCConnectionFactory.create(JDBCConnectionFactory.java:65)com.service_now.mid.connections.ConnectionCachePool.getAvailableConnection(ConnectionCachePool.java:82)com.service_now.mid.connections.ConnectionCache.get(ConnectionCache.java:94)com.service_now.mid.probe.JDBCProbe.getJDBCConnection(JDBCProbe.java:769)com.service_now.mid.probe.JDBCProbe.probe(JDBCProbe.java:117)com.service_now.mid.probe.AProbe.process(AProbe.java:103)com.service_now.mid.queue_worker.AWorker.runWorker(AWorker.java:122)com.service_now.mid.queue_worker.AWorkerThread.run(AWorkerThread.java:20)java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)java.lang.Thread.run(Thread.java:748)at com.service_now.mid.probe.JDBCProbe.getJDBCConnection(JDBCProbe.java:773)at com.service_now.mid.probe.JDBCProbe.probe(JDBCProbe.java:117)at com.service_now.mid.probe.AProbe.process(AProbe.java:103)at com.service_now.mid.queue_worker.AWorker.runWorker(AWorker.java:122)at com.service_now.mid.queue_worker.AWorkerThread.run(AWorkerThread.java:20)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)at java.lang.Thread.run(Thread.java:748)ReleaseApplies to any Release.CauseThe connection between the mid server and the database fails.Resolution(1) Confirm with the database administrator that the database listener is up and running on the port defined in the data source, e.g. 1521, 1433(2) Confirm the connection properties in the data source are correct for the database machine you are connecting to, check Server, Database port, Table name, Database name, Type must be JDBC, set the Use Mid Server to one that is not part of a mid server cluster and is up and running(3) From the mid server machine open a terminal window and issue the following telnet to confirm the connection happens:telnet <hostnme or IP address of database machine> <port of database listener>Example:telnet 10.1.2.3 1521Note if the mid server is a windows machine, but does not have the telnet client enabled enable it - check google for you specific version of windows, e.g. for win 10:https://kencenerelli.wordpress.com/2017/07/16/enabling-telnet-client-in-windows-10/(4) If the telnet connects ok, run wireshark (installable from the web) on the mid server machine and collect a packet trace to be sure the mid server machine is communicating with the database when you do a load or test load.If steps (3) or three (4) show no connectivity between the mid server machine and the database check the network routing and the firewall rules with your network team to be sure network connectivity is allowed between the mid server machine and the database.