iOS 11 - Mail Sync issue with Exchange 2016 / O365 /

If you are running Exchange 2016 users may fail to sync mail after upgrading to iOS 11

Some combinations of O365 and may also be effected

Official Apple Statement

Microsoft Statement

Reddit article

We have tested successfully on Exchange 2010. Good topic for this forum.

I have also tested successfully with a mix of 2010 and O365 and stand alone O365 with no issues.
Suspect this has to be a pretty specific scenario.

It seems that this is a server 2016 issue, and office 365 is a mix of server 2012 and 2016. Therefore if you’re unlucky enough to have your tenant on 2016 you will experience the problem (no way to tell externally what OS it is running on afaik).

iOS 11.0.1 has been released to fix this issue.

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yes, i am agree with you. I have recently upgraded to iOS 11. After upgrading, I am unable to access the emails, even the email not loading or working. i visit Apple Customer Service Number follow the steps to solve this issue but after 4-5 days mail sync issue occurs. I am using Ms Office 365 on my phone. How can i able to solve this issue?

Issue described in this post only impacts devices running iOS 11.0, if your device is running iOS 11.0.1 or later this issue would not longer apply.

You should reach out to Apple or your email service provider for assistance.