Thank you for the response. I looked the document, but sqlnet.ora file settings is already like that. (with ON option)
Any other suggestion please.
posted the wrong URL above - should have been:
Oracle Support Document 2473789.1 (OBIEE 12c: Reports Failed With Error ORA-03113 Intermittently) can be found at: https://support.oracle.com/epmos/faces/DocumentDisplay?id=2473789.1 instead of https://community.oracle.com/message/15021434?et=watches.email.thread#15021434
If disabling Out of Band Breaks doesn't work, this is another option to try.
Thank you. I think it solved our problem. We did not receive any such error.