No data to retrieve?

Hi All,

I have created a universe with 6 tables and 2 alias tables, and exported the universe.

I had generated the report first time the data is coming as only with 1 page(200 records), the fields are EMP ID, P.ID, Revenue, Salary, and saved the report to repository.

when I run the second time it is showing only 7 records of the reports, I am opening today the pop up message ass "NO data to retrieve " and it is taking too long for opening the report.

Kindly help me where I did a mistake?

Note: in the universe some of the tables relationship is N-N.

Thanks in advance....