Yesterday afternoon, our connection to Oracle inexplicably stopped. It's up and running, but we can't connect via Oracle SQL Developer nor our ERP which uses Oracle for all of it's data tables.
Our version of Oracle is 11g and it's on Windows Server 2008 R2 (VM in Hyper-V). We've had Oracle up and running for years and we made no changes before this loss of connection.
We rebooted Oracle. We rebooted the entire server. No success. We eventually narrowed it down to an issue with the listener. The odd thing is that the listener is running, we can ping it with a status request and get a response using command prompt ‘lsnrctl status’, but the response takes 3 or more minutes. We have stopped and restarted the listener, but it has not restored connectivity. Again, SQL Developer and our ERP are not connecting at all.