Forum Discussion
OneNote fails to open when using "Open in app" from Teams
A first-time poster... be kind 🙂 I’ve searched the posts and haven’t found a similar complaint, so here it goes… In Teams (web or app), a OneNote file stored in a Teams channel can be opened...
majani hello!
I think I managed to get a workaround by opening the notebook from the OneNote Windows 10 app.
I don't remember for sure though, sorry!
ps. MS support for OneNote isn't the best, unfortunately. They essentially ditched OneNote 2016 and moved to OneNote Windows 10, I have heard they are ditching this version again and making a completely new app! 
thank you for your answer. i was able to solve the problem this morning. i had to create a proxy exception in my firewall with the URL onenote.com. after that it works fine. it can be that simple sometimes. 🙂