Very Specific Microsoft Outlook Add-In Error (Windows 10 version 1903)
I'm running into a strange Add-In issue specific only to Native Outlook running on Windows version 1903. Our Add-In works for Native Outlook running on Windows versions later than 1903 just fine.
The problem is that when you open our web Add-In in Native Outlook, you should be able to click a div which triggers a network request and then changes the state of the application in React. The actual behavior is that no network request is triggered and the state is not changed. Again, this behavior works fine on Windows 10 versions later than 1903.
I've tried logging the behavior using Microsoft Edge's DevTools, but the only error I see is XML5632: Only one root element is allowed. at index.html (1,1). This is the only output from the Add-In that I can see-- none of my console logs actually show up in the console.
My guess is that perhaps the JavaScript rendering engine responsible for running web-based Microsoft Add-Ins on native Outlook for Windows version 1903 is not Chromium-based, thus a bug in how the JavaScript rendering engine (pre-Chromium Edge?) interprets the XML and/or JS, but again that's just a guess.
I've tried a number of things, including removing the <?xml version="1.0"?> tag at the top of the manifest.xml file and tweaking some of the parameters of the xmlbuilder.create() function that we use to build the XML file to no avail.
The node module xmlbuilder is being used to generate the manifest.xml, but I haven't found any issues with it so far.
In any case, I would be grateful if anyone that has run into this issue before has any ideas, suggestions, fixes, or workarounds because at this point I am totally stuck.
This Microsoft Edge WebView for Office Add-ins post describes which versions of Office and Windows support Edge WebView (and previous versions will use IE for the web view control).
On versions of Windows before 1903, the HTML/JS engine used, is Internet Explorer. After 1903 it uses pre-chromium Edge (also depends on the version of Office).
It is likely your code is using something that IE is not compatible with. You can debug iexplore.exe directly in script mode with Visual Studio. It may also help to make sure "Disable Script Debugging" is not checked, and also "Display a Notification about every Script Error" is checked. Open IE -> Tool -> Internet Options -> Advanced Tab.