Hi, I don't know about AIX nor Autosys, but it one possibility seems to be related with the environment of the Oracle user's account used to connect . The Oracle user's account you tested via sqlplus, is the same used by the Autosys? Maybe an after-logon trigger on the database, and for that user it is defined, which fires the ORA-0001 depending on the tools used???? regards We have a setup where the jobs are run through Autosys on the Oracle 9.2 server (AIX 5L). I've installed oracle client 9.2 on another AIX box. I can connect the database via sqlplus and also able to tnsping. The problem is that, the autosys jobs are not able to run while its logs are throwing following errors: Attempting (1) to Connect with Database: <servername> Oracle Logon Error: ORA-65535 and ORA-00001 Oracle Logon Error: Unable to display error message for ORA-65535 and ORA-00001 I couldn't find any details for ORA-65535 error. Also turned sqlnet logging on but the trace files don't reflect any error, even not the ora-65535 or ora-00001. $TNS_ADMIN is set to /usr/vendor/oracle/9i/9.2.0/network/admin. Permissions on tnsnames.ora are -rw-rw-r-- 1 oracle dba 502 Aug 06 00:31 tnsnames.ora which is actually the same as the other boxes running fine with autosys. Can anyone please highlight what can be the problem here? Thanks.