BEA-001129: Received exception while creating connection for pool

While starting the Weblogic Admin / Managed servers, we get the Connection pool error 

Error Message - 

<Warning> <JDBC> <BEA-001129> <Received exception while creating connection for pool "conpoolname": ORA-01034: ORACLE not available

ORA-27101: shared memory realm does not exist

<Error> <JDBC> <BEA-001112> <Test "SELECT 1 FROM DUAL" set up for pool "Conpoolname" failed with exception: "oracle.jdbc.xa.OracleXAException".>

<Warning> <JDBC> <BEA-001129> <Received exception while creating connection for pool "Conpoolname": ORA-01034: ORACLE not available

ORA-27101: shared memory realm does not exist

Solution - 

The issue mostly is that the Datasource is not able to connect to the Oracle Database.

1. Login to the Admin server, navigate to Services -> Datasources

2. Go to Monitoring tab -> and do a Test Datasource.

3. If the issue still persists, go to the putty session, navigate to the <domain path>, and select 'config', 'jdbc' folders. check the jdbc.xml if the datasource values are correctly entered.

 4. After validation, restart the admin/managed server