I'm upgrading the GroupDocs version used in my app fro 2.17 to 2.19. With 2.17 all documents I've tried preview properly. With 2.19 all documents begin to render. I see the "Loading your content" message. The display is then replaced with "This document is in a format which cannot be viewed by the previewer." I see files created in the viewer cache.
My code is unchanged other than copying the handler definition from the updated GroupDocs documentation. I use the Stream method of the ClientHelper object to provide content to the viewer.
Are there code changes I need to make to be compatible with 2.19?
Never mind. Running several more times to narrow down the problem caused it to go away. I assume something must have been cached across iisreset or cache deletes that eventually cleaned itself up.
All documents that previously failed are working for me now.
And now it's back. Sometimes the initial preview works properly then the error appears when going to the next page.
What problem is GroupDocs detecting that gets reported as "This document is in a format which cannot be viewed by the previewer"? It's not as simple as a bad document. For the same document I see the problem sometimes on pages that have previously rendered successfully.
We are sorry to hear that the issue is back. In this month we will release a new generation of the Viewer which will have more features and flexibility. Because of that will no longer release the current Viewer (your library will continue to work and you can continue to use it). So, I can advice you to wait for the new product and to try to use it - there should be no such issues.
In same time could you please share with me your Web.Config and describe your IIS configuration?