A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Hello Amith Kumar
Welcome to the Microsoft Community.
Thanks for your report for this problem. We've made a few tests on our test devices, and confirmed this is a service unavailable issue currently. Right now there's a workaround which is to use the online OneNote, where you can still use immersive reader feature normally.
We are continuously running tests on different devices and accounts in order to gain further insight into the problem in a variety of circumstances, and to gather essential technical information to report this problem to Microsoft. We sincerely recommend you wait for some time for a fix. You can also click the feedback button in the top-right corner in OneNote to report this problem to the OneNote team.
Thank you for your understanding and support!
Best Regards,
William.Y | Microsoft Community Support Specialist