Some reasons that a connection attempt to an Oracle database might fail are:
The OpenEdge schema holder is not connected.
The Oracle process is not running, or not running correctly. Try to connect with SQL*PLUS to check the status of the Oracle RDBMS.
The value of the ORACLE_SID environment variable that started up the Oracle process is different from the current value of ORACLE_SID.
The user ID and password combination you provided during connection is invalid for the Oracle database.
For a remote DataServer connection failure, you didn't include the correct name of the host and server in the network. Be sure to enter the same server name you used when you started the broker.
Error messages about mismatched code pages are caused when -cpinternal and -cpstream do not match the code page that the Oracle database uses.
The OpenEdge schema holder is not connected.