Microsoft Outlook cannot forward any email to external address

If your users create outlook rule to forward their emails to an external email address automatically, these rules will not work and the forwarded email will never leave your exchange server.

By default, Exchange server blocks any automatic forwarding message. To solve this problem you will need to follow the below steps.

Exchange 2013 and PowerShell

In Exchange 2013, the only way to view or change the configuration for automatic replying and forwarding to external address is via the Exchange Management Shell (EMS) with PowerShell commands. These PowerShell commands can also be used with Exchange 2007 and Exchange 2010.

To get the currently configured Remote Domains, use:

Get-RemoteDomain

The following command will see the current configuration for this remote domain use:

Get-RemoteDomain Default | fl

In the result list, look for the settings for AllowedOOFType, AutoReplyEnabled and AutoForwardEnabled. You can directly filter your results list for these properties by using:
Get-RemoteDomain Default | fl AllowedOOFType, AutoReplyEnabled, AutoForwardEnabled

To change the settings, use the Set-RemoteDomain command.

§  Enable automatic replies
Set-RemoteDomain -AutoReplyEnabled $true

§  Enable automatic forwards
Set-RemoteDomain –AutoForwardEnabled $true

§  Enable OOF for Outlook 2003 and previous (for Exchange 2007 and 2010 support)
Set-RemoteDomain –AllowedOOFType $ExternalLegacy

To change all these properties at once, you can use:
Set-RemoteDomain Default -AutoReplyEnabled $true –AutoForwardEnabled $true –AllowedOOFType $ExternalLegacy

Exchange 2007/2010

In Exchange 2007/2010 “Internet Message Formats” is replaced by “Remote Domains”

1. Open Exchange Management Console

2. Organization Configuration

3. Hub Transport

4. Remote Domains tab

5. Right click properties on Default

6. Message Format tab (for Exchange 2010) / Format of original message sent as attachment to journal report (for Exchange 2007)

7. Check “Allow automatic forward”

Exchange 2003

1. Open Exchange System Manager

2. Expand Global Settings

3. Locate Internet Message Formats

4. In the right-hand panel, right click Properties on “Default”

5. In the Advanced tab, check the option “Allow Automatic Forward”