previously developer 6i with oracle 10g, 11g had a connection problem that fixed using this script
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
ALTER DATABASE CHARACTER SET INTERNAL_USE UTF8;
but this script doesn't work with oracle 12c
is there any solution ??????????????????????
Attempting to connect from 9.2 to 12.1 will fail with an "ORA-28040: No matching authentication protocol" error.
The above is what you can read within official Oracle documents. Developer 6i is an 8.0.6 Client version, so....
See MOS Doc ID 207303.1 Client / Server / Interoperability Support Matrix For Different Oracle Versions.
Developer 6i ?!? wouldn't be time to upgrade ?