When running a report you get this error message.
This can happen for various reasons. To see the error explanation, you need to look at the Reporting Server log.
This log is on the machine where your Reporting point server resides :
In SQL Server Reporting Services 2016 or earlier: C:\\Program Files\\Microsoft SQL Server\\MSRS13.MSSQLSERVER\\Reporting Services\\LogFiles
In SQL Server Reporting Services 2017: C:\\Program Files\\Microsoft SQL Server Reporting Services\\SSRS\\LogFiles
Open the log file (using CMTrace) - ReportServerService_.log and run the report. The detailed error will be displayed.
If you need any help, contact our support team and include the log file to your request.