CABI Jaspersoft 6.3
After checking the Tomcat log, no definitive cause was determined. However when we tried another browser, we were able to pull up reports.
We are using Chrome browser. We tried using Incognito mode, and the reports worked. We determined that an ad-blocking extension "uBlock" was blocking a request that got made when running the report. Once we disabled uBlock for our CABI server's domain, the reports are running perfectly.