Product ProgressĀ® TelerikĀ® Report Server
Operating System Windows


As of Telerik Reporting R2 2017, the Report Server and HTML5 Report Viewer require a browser supporting promises.

The error indicates that the used browser does not support promises.
Please follow the HTML5 Viewer: Important Settings article which contains the requirements for promises.


Add a promise polyfill to the page, such as Polyfill.io.

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