Thanks for providing the required details.
We investigated your reported behavior at our end and found that when getting information about your provided .msg file using ViewerImageHandler, GetDocumentInfo gives page count = 5, whereas GetDocumentInfo with ViewerHtmlHandler gives page count =1. The reason behind this behavior is that in image-based rendering it is not appropriate to convert a large document into a single image, therefore, the API breaks down the provided document into 5 pages and renders each as a separate page. However, in the case of HTML based rendering, GetDocumentInfo returns page count =1 and the whole document is converted into a single HTML page.
To avoid any issue, please make sure that you are using the appropriate ViewerHandler when getting document information as well as when rendering the document. For reference, we have created this (109.3 KB) sample application for you that will demonstrate how to use the appropriate ViewerHandler. Hope it helps.
No problem at all. You can try again and share your feedback with us.