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Salesforce Email-to-Case Bounce Back Loop Creates Thousands of Cases

Udgivelsesdato: Jun 28, 2026
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What Is the Email-to-Case Bounce Back Loop?

When Email-to-Case is configured with an auto-response rule, the system can enter an endless loop if the return email address for the case submitter does not accept incoming emails. In this scenario, the case routing address sends an auto-response, the response bounces back, and Salesforce treats each bounced message as a new incoming email — creating a new case each time.


Salesforce Email-to-Case has a built-in loop detection mechanism. After receiving more than 15 emails within 60 seconds that share the same Subject, Sender, and Body content, the loop detection triggers and stops creating new cases for that time period. However, due to environment processing variables, slightly more than 15 cases may be created before the limit takes effect.

Common Causes of Email-to-Case Loops

The following configurations are known to trigger Email-to-Case bounce back loops:

  • "Out of Office" auto-replies sent in response to a Case Routing Email Address
  • Case Auto-Response Rules where the "Reply To" or "Sender's Email" address is set as the Case Routing Email Address
  • The Case Owner (either a Queue or a User) has an email address that is also an active Email-to-Case routing address
  • Improperly configured Workflow Rules or Email Alerts that send messages back to a routing address

Error Message You May See

The Automated Case User — the system user that creates case records when Email-to-Case processes inbound messages — may receive the following error notification when a loop is detected:

Subject: Email-to-Case: Error(s) encountered while processing

The following errors were encountered while processing an incoming email: LIMIT_EXCEEDED: A loop was detected in Email-to-Case processing

This message confirms that Salesforce detected and halted the loop.

How to Find the Automated Case User Setting

The Automated Case User is configured in Support Settings. To navigate there:

  • In Salesforce Classic: Go to Setup, then Customize, then Cases, then Support Settings.
  • In Lightning Experience: Click the Gear icon, go to Setup, then Feature Settings, then Service, then Support Settings.
Løsning

Resolution: Preventing and Fixing the Email-to-Case Loop

The Email-to-Case bounce back loop occurs because the routing address is receiving emails it should not process. The fix involves reconfiguring how bounced or auto-reply messages are handled so they never reach the Salesforce routing address.

Step 1 — Redirect Bounced and Out-of-Office Emails Using an Outlook Filter

Work with your IT team to create an email folder and filter rule in the Outlook account associated with your Email-to-Case routing address. This prevents bounce-back and out-of-office messages from landing in the inbox, which is where Salesforce monitors for new incoming cases.
For example, IT can create a folder called "Bounced Messages" in Outlook. Then, create a filter rule that checks the Subject line of all incoming emails. If the subject contains values such as "Out of the office," "Undeliverable," or similar error phrases, the rule routes those messages to the "Bounced Messages" folder instead of the inbox. This stops those emails from being processed by Salesforce Email-to-Case.

Step 2 — Review and Correct Auto-Response Rule Configuration

Check that the Case Auto-Response Rule's "Reply To" and "Sender's Email" addresses are not set to the same address as the Case Routing Email Address. If they match, any auto-response Salesforce sends will be received by the routing address and treated as a new inbound case, restarting the loop.

Step 3 — Check Case Owner and Queue Email Addresses

Verify that the email address for each Case Owner user or Queue is not an active Email-to-Case routing address. If the owner's email is a routing address, any case assignment notification sent to the owner will be processed as a new inbound case.

Optional Step — Add a Validation Rule to Block Specific Subject Lines

If the loop is triggered by emails with a predictable subject pattern, such as "OOO" for out-of-office replies, you can create a Salesforce Validation Rule on the Case object to prevent new cases from being created when the subject contains that keyword. For example, the formula CONTAINS(Subject, 'OOO') will block case creation when the subject includes "OOO."

Vidensartikelnummer

000385835

 
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Salesforce Help | Article