iOS 11 – Cannot Send Mail. The message was rejected by the server.

I am knee deep in  an upgrade from Exchange 2010 to Exchange 2016 in the office. There have been many challenges that I will be addressing in another post, however I thought this one regarding iOS 11 to be important enough to write about it today.

Cannot Send Mail. The message was rejected by the server.

I have one user on the network that is receiving this message when they attempt to forward or reply to their mail on my exchange server. When composing a new message the mail is delivered as expected. The fact that this is a new server and the user was migrated just days before led me to believe the issue was on my end.

Failed Fixes:

  • Restart IIS with an IISRESET command
  • Remove the email profile from the iPhone and recreate it
  • Restart the entire exchange server
  • Review the log files for any clues.

None of the above was able to fix her issue. Further more, my own iPhone was on iOS 11 and at least a dozen other users had upgraded and their devices were working properly.

I was about to give up when I stumbled across this article today from Apple Continue reading “iOS 11 – Cannot Send Mail. The message was rejected by the server.”