Below is quote from my response in your support ticket on the same question:
If you are using the HTML5 Viewer, please check if you have CSS rule(s) setting the width and height of the DIV element with the ID of the viewer object.
Also if you are using a Table item to visualize data in the report, test if setting the viewer's ViewMode to PrintPreview allows you to preview the rendered HTML in browser. The reason for this suggestion is that some browsers, like IE, have limitation for the number of HTML elements in the loaded pages, and as a result content may not be displayed - Design Considerations for HTML Rendering.
Please let us continue the discussion in one of both threads in order to keep a better track on the exchanged information.
Thank you fro your understanding.
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