sqldeveloper error message: Network adapter could not establish the connection error

Question

I had made connection to the remote oracle database through sqldeveloper on my system. Suddenly the power went down and I had to restart the system. Now, when I am trying t

Answer 1

In the connection properties window I changed my selection from "SID" to "Service Name", and copied my SID into the Service Name field. No idea why this change happened or why it worked, but it got me back on Oracle.

Answer 2

I just created a local connection by breaking my head for hours. So thought of helping you guys.

• Step 1: Check your file name listener.ora located at

  C:\app\\product\12.1.0\dbhome_3\NETWORK\ADMIN

  Check your HOSTNAME, PORT AND SERVICE and give the same while creating new database connection.

• Step 2: if this doesnt work, try these combinations give PORT:1521 and SID: orcl give PORT: and SID: orcl give PORT:1521 and SID: pdborcl give PORT:1521 and

  SID: admin

If you get the error as "wrong username and password" :
Make sure you are giving correct username and password

if still it doesnt work try this: Username :system Password: .

Hope it helps!!!!

Answer 3

Check the listener status to see if it is down:

ps -ef | grep tns

If you don't see output about the listener:

oracle 18244 /apps/oracle/product/11.2.0/db_1/bin/tnslsnr LISTENER -inherit

Then you will need to start it up. To do this, execute the lsnrctl command.

Type start in the LSNRCTL> prompt.

Answer 4

Check The port 1521 in your server. May be its blocked by firewall. Or disable firewall and try.

Answer 5

I had this error after fresh Oracle installation.

To fix this I've launched Net configuration assistant (from start menu or netca.bat in the bin folder) and simply added a Listener.

Answer 6

This worked for me :

Try deleting old listener using NETCA and then add new listener with same name.