Got this Report error, when I was importing a Managed Solution contains a report to an organization.
Later I opened the report and found that there was a problem with the expression.
The problem is,
I have used “=TOday()” (Capital letter ‘O’, instead of small letter ‘o’) in an expression.
Updated the expression “=Today()” and uploaded the Report rdl file.
Took the latest Managed Solution with the latest rdl file and solution imported successfully.
Issue resolved. Hope this helps 🙂