Join Configuration Error In Oracle

I need some help here to fix this error. Let me brief you about it. I was opening a discoverer report by logging through a user when I got this error as Attempt failed to open workbook.
Sometimes the error is a bit different like OracleBI Discoverer was unable to find worksheet that was requested.
BIB-10310 an unknown exception error occurred.
The methods I tried to resolve it was that I turned off “Fan trap Detection” but yet it doesn’t works. I know I have one to many relationships in the sheets but I don’t think it might be due to this.
Please it's an urgent need of mine to get this issue resolved.
Can you help me out?
OracleBl Discoverer
Join configuration cannot be resolved.
Reason: more than 1 of the detail folders
users non-aggregated items. Attempt to
open workbook failed.
