We are running CRM 2016 with the latest updates.
All of our out-of-box reports, such as the Account Overview or Sales History work just fine. But any custom report we create fails to run. They all throw an error with "Invalid User Authentication. The user authentication passed to the platform is not valid."
I've double-checked the permissions on SSRS, and our CRM service account appears to have the correct permissions set, and they are also a member of the PrivReportingGroup and SQLAccessGroup AD groups.
Does anyone have any ideas for why all the standard CRM reports would function just fine, but all custom reports would fail?