We're using an OutlookJS add in that fetches data from a web service we developed. After the recent Outlook Desktop update (Version 2402 (Build 17328.20142)), the fetch request made in the onMessageCompose event fails with the error No valid origin in response.
What's weird is, if we call the same method from a task pane, the fetch request goes through without an issue. It also works perfectly in Outlook Web and the new Outlook. This leads me to believe the onMessageCompose uses different/stricter CORS rules, but can't figure out what would fix the issue.
Does anyone have an idea what to do?
Thanks!