Sending emails with attachments fail under iOS using Exchange ActiveSync protocol on Windows Server 2016


SYMPTOMS

When you forward or reply to an email when using the native iOS 11 mail application with Exchange ActiveSync against MailEnable running on Windows Server 2016 you receive an error message "Cannot Send Mail. The message was rejected by the server."

CAUSE

This is cause by a bug in the iOS 11 release, which was resolved in 11.0.1.

RESOLUTION

This was resolved in iOS 11.0.1. Upgrading iOS will resolve the problem. It can also be resolved by disabling HTTP/2 on the Windows server. This is done by adding the following Windows registry keys and rebooting the server:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters]
"EnableHttp2Cleartext"=dword:00000000
"EnableHttp2Tls"=dword:00000000

MORE INFORMATION

https://support.apple.com/en-us/HT208136

 

 



Product:MailEnable (All Versions)
Article:ME020667
Module:General
Keywords:ios,11,windows,server,2016,reply,forward,fail
Class:PRB: Product Problem or Issue
Revised:Friday, September 29, 2017
Author:
Publisher:MailEnable