Unable to export a PDF/CSV file from TrueSight Presentation Server console (logged as admin user) from License Usage - Server Endpoints section
NOTE: the Data Consumption report is working OK and the PDF/CSV report can be generated

1. On the TrueSight Infrastructure Management server modify the file located at: <installationdirectoy>\pw\custom\conf\pronet.conf

2. Add the following property:com.bmc.licensereports.allowDownload=true

3. On the TrueSight Infrastructure Management server execute command: pw jproperties reload

4. Generate PDF/CSV file from License Usage - Server Endpoints and export it.

5. Once exported, change the property value from step 1 to false or delete the property from the configuration file and execute again the command: pw jproperties reload

NOTE: also check KA 000371836 to address error message: "System error."

If after following the above steps the problem is not resolve, please run the Health Check report on the affected TrueSight Infrastructure Management server and if there are errors related to MaxHeap or MinHeap please follow the User actions provided in the report to solve those errors, this may resolve this problem.
As a general note, it is recommended to run the Health Check report in regular basis and correct all the errors and warning present in the report.