ETL job errors for few tables while loading data to FTI HD

Problem Summary
---------------------------------------------------
ODI-1227: Task SrcSet0 (Loading) fails on the source ORACLE connection ORACLE_OTM

Problem Description
---------------------------------------------------
We have encountered this error when ODI try to load data to FTI database.

ODI-1227: Task SrcSet0 (Loading) fails on the source ORACLE connection ORACLE_OTM.

The ETL process can load some table (not table specific) with STATUS = SUCCESS, but failed on loading data to other tables.

Moreover, We are not able to see any error log in ociagent log from the file /apps/odi11g/oracledi/log/ociagent.log file

Needed help on below points :

1. How can we turn on more log entries to get detailed error logs for ETL related process.
2. Why connection ORACLE_OTM failed only certain table load & works for others smoothly ?