Last updated: October 2016
If you use OneNote 2016 for Mac and OneNote for iPad or iPhone, you may be asked to sign in any time you open OneNote or switch between notebooks. Similarly, OneNote may require you to sign in repeatedly in order to resolve sync errors.
This issue has been fixed for OneNote for iPhone and iPad. To get the fix, update to version 15.27, which was released on 10/6/16. Once you update the app, OneNote will ask you to sign in again. After you do so, the repeated prompting for your credentials should no longer occur.
The fix for the same issue in OneNote 2016 for Mac is available in 15.27 (161010), which was released to Insider Slow users on 10/10/16, and to non-Insiders on 10/11/16. Again, be sure to sign in when prompted; after that, the repeated requests to sign in should stop.
Have a feature request?
We love reading your suggestions on new features and feedback about how you use our products! Share your thoughts on the OneNote UserVoice site. We’re listening.