Guidelines for Email System Forwarding with Email-to-Case

Email-to-Case uses information in the email headers to match an email to a case. If your email system’s forwarding changes the headers, Email-to-Case can’t identify the related case and add the email to the thread.

The steps to set up forwarding depend on your email provider. Before you start, give your email admin the email service address generated in Salesforce. This address is the address to forward to. To locate it, in Setup, go to the Email-to-Case page. In the Routing Addresses section, each routing address lists an auto-generated email service address.

Warning When you forward emails to Email-to-Case, we strongly recommend keeping a copy in your inbox. This provides a backup of your inbound communication, in the event that one of your customizations unexpectedly causes issues in Email-to-Case.

To allow Email-to-Case to thread emails to cases correctly, follow these general guidelines.

• Configure one routing address to use in forwarding. When customers address emails to multiple service addresses, emails don’t thread to cases as expected.
• Avoid defining aliases that map to the same Email-to-Case service address. For example, some companies define aliases specific to a country, such as support-us@mycompany.com and support-uk@mycompany.com, that point to the same support address, support@mycompany.com. If a customer sends an email to support@mycompany.com and the support-us@mycompany.com alias, the email system forwards multiple copies of the same email to Salesforce. As a result, Email-to-Case creates multiple cases and emails aren’t threaded properly.
• Avoid email rules that add disclaimers or tags before or after the email subject, such an [External] tag on emails that originate outside of the company. Changing the subject can break threading on some email clients. If your customer tries to reset the email subject, that change can also reset the email headers used in threading.

Example: Set Up Forwarding in Microsoft Exchange 365

Tip Check the Microsoft 365 support website for specific setup steps. This example gives general guidelines to help email admins set up forwarding with Email-to-Case.

If Microsoft Exchange 365 is your email system, ask your email admin to set up forwarding in the Exchange Admin Center. We recommend that you avoid user-configured rules. When users apply redirect or forward rules in Outlook settings, those rules can alter email headers and impact threading. Some companies can also restrict users from forwarding to external domains.

Go to the Exchange Admin Center and create a contact. For the contact’s email address, copy in the email service address generated in Salesforce. Then, configure forwarding using these options.

Option	Description
Full Inbox Forwarding	Recommended. This option preserves email headers and can be configured to keep a copy of incoming emails in the user inbox. In the Exchange Admin Center, select the support mailbox under Recipients and enable forwarding. Specify the contact’s email service address generated by Salesforce as the address to forward to.
Mail Flow Rules	Recommended. When applied by the Exchange admin in the Exchange Admin Center, a redirect rule preserves headers during forwarding. Have your Exchange admin create a rule that’s applied when an email recipient includes your support address, such as support@mycompany.com. Define the rule to redirect the email to your contact’s address, which is the email service address generated by Salesforce. Because user-applied rules cause header changes that break threading, we don’t recommend that users create rules in Outlook settings. If a user configures a forwarding rule in Outlook settings, Email-to-Case can't identify the sender because the mail system strips out the original sender address.
Distribution Lists	If your support address doesn’t map to an actual user, a distribution list is a good method to forward emails to Email-to-Case. In the Exchange Admin Center, create a distribution group and add the email contact that you created as a member.