One of the user is trying to run a report through SSRS report builder from his computer. The same report would work through the SSRS reports website. But when he runs from his computer it fails. On the Report builder - test connections on Data source succeeds.
It errors out with "microsoft.reportingservices.diagnostics.utilities.accessdeniedException". Here is a screenshot. The results Google produced did not help.
http://screencast.com/t/nlxsprwQBefw
Sorry to necro-post, but I had the same issue and @djangojazz's answer is almost correct, there are actually 3 steps:
After doing these steps on SQL Standard 2016 (version 13.0.4422.0) / Report Builder 3 (version 14.0.609.142), the user was then able to preview reports without having to give them full server admin rights / etc.