iOS 11 issue?

Iron Contributor

Microsoft made an urgent announcement in the Office 365 admin web to not install iOS 11 because it will disrupt sending and receiving emails if you are accessing Exchange email from the iOS 11 mail app,, O365, and Exchange 2016.

Some of our users already installed iOS 11 and they are still able to send and receive emails.

Are there specific Outlook email features that would not work with iOS 11?

When will this restriction be rescinded?




10 Replies

Outlook for iOS is fine and not affected by these compatibility issues as I understand it.  This is only when using the native email app with an Office 365 mailbox, as well as the other scenarios you have mentioned.  This is where you might see an error message that says "Cannot Send Mail. The message was rejected by the server".


A fix is being worked on asap, as is also confirmed here - If you can‘t send an email with iOS 11 and an or Exchange mail account - "Apple is working closely with Microsoft to resolve the issue and will release a fix soon in an upcoming software update".

The employees who upgraded to iOS 11 are using the Apple native mail app connecting to their Office 365 Exchange Online accounts. They  are able to send and receive emails.


Very confusing announcement.

That's interesting.  Now you mention it, I have seen other reports that not everyone is affected by this, so your mileage may vary.  With Apple and Microsoft confirming the issue, it's must be a thing but we will have to wait for additional guidance before we have any more particulars.  Confusing indeed!


Hey all - happy to help clarify this. What is the confusing piece?

Microsoft's announcement states that users who upgrade to iOS 11 and they use the Apple Native Mail App to connect to Exchange Online or Exchange 2016 will have email send and receive problems.


Some of our employees upgraded to iOS 11 - they use the Apple mail app to connect to their Exchange Online email. They are still able to send and receive email.


In other environments, users in this scenario are not able to send and receive emails anymore.


Teg Badhan posted this article:


Not sure if Microsoft will patch their Exchange 2016 back end servers to resolve the issue. Any ETA as to when Microsoft and Apple will roll out a fix for this issue?



Apple is going to release a patch to fix the issue (as it is technically on their client side). However, we are also rolling out an emergency fix on our service side. That is in process of rolling that explains why some users are not impacted while others are.

As for Exchange 2016 on-prem, the support article explains how to mitigate: Either way though, Apple will fix on their side soon so this workaround will only be temporary.

Thanks for the update Allen and the explanation, must be a huge task to deploy a fix at short notice.

Is this issue fixed?


Found this article today:


Could you please confirm?

Thank you.

best response confirmed by Emy Loanzon (Iron Contributor)

Yes, this is confirmed in the Apple support article I linked to previously, which has been updated to say this been fixed in the iOS 11.0.1 update, which is now available. 

Thank you!