Mail Error: Using Microsoft Apps for Email? Wait before upgrading to iOS 11.
If you use your iPhone and/or iPad for email using Microsoft applications you are advised to refrain from upgrading to Apple’s new operating system, iOS 11, due to mail error issues.
Due a compatibility issue, it is not currently possible to send or receive emails using Office 365, Outlook.com and Exchange 2016 on the new operating system.
The following mail error message pops up
“Cannot Send Mail. The message was rejected by the server.”
After a slew of complaints from users on social media following the launch of iOS 11, both Apple and Microsoft have confirmed that they are aware of the problem. The issue stems from the fact that the new operating system is not compatible with Microsoft servers.
Apple and Micrsoft are working closely together to develop a fix for the next software update.