File Error Data may have been lost

in OTBI - BI Publisher report that has multiple tabs is showing this error on opening the excel file. File error : data may have been lost 

Users are able to provide a specific transaction that should be in the date range they used to get the report - but is not being included in excel -this makes us think that indeed some data may be lost. Just posting this here to see if any expert has solved for this.

OTBI is being used from cloud offering.