In our integration, on first load the page is empty and an unhandled exception is thrown. and the exception is file not found error.
Which seems to be a fairly common error.
One thing that I observed when I am debugging is that it never came to the Page load method. Which makes me think that there could be something in the Groupdocs that is preventing it from loading.
However, after refreshing the page, the file loads just fine. This always happened.
Please see attached screenshot.