3731791 - Outbound Email Delivery Failures and Bounces in SAP Service Cloud Version 2

• Outbound emails sent from SAP Service Cloud Version 2 or SAP Sales Cloud Version 2 fail with delivery errors or bounce messages.
• Examples of errors include:
  • 5.3.0 - Other mail system problem
  • 554 - "The user 'anonymous' is not in the email contributor group."
  • Other observed behaviors:
    • Email is not delivered to the recipient
    • No response or follow-up email is received
    • Bounce message is returned to the sender
    • In SAP Service Cloud Version 2, the timeline email card may display (under the email body):
      • Permanent - OnAccountSuppressionList
      • Example technical details:
        Recipient Address: test@example.com
        SMTP Status Code: 5.1.1

• SAP Service Cloud Version 2 1.0
• SAP Sales Cloud Version 2 1.0
• SAP-managed MTA (Amazon SES) or customer-managed MTA
• External recipient systems (e.g., Microsoft 365, Exchange, Other) 

1. Send an email from a case or any other supported application via the email channel to a recipient address.
2. Observe in Outbound Email Monitoring that the message status is “Sent”.
3. Check the bounce/return message (in the mailbox defined by the return path or in Inbound Email Monitoring) showing either:
   • “Permanent – OnAccountSuppressionList”
   • SMTP 5.1.1, and possibly “554 MessageRejected”
   • or any other 5.x.x error

• The error originates from the recipient mail system, not from SAP.
• The suppression would be done by either Amazon SES or the customer's own MTA provider.
• The errors indicate a permanent delivery failure (SMTP 5.x.x).
• The potential root causes depends on the recipient mailbox configuration or status. Below are some examples: 
  1. Mailbox exists but rejects external/anonymous senders
     • Mailbox only accepts authenticated or approved senders
     • External senders are treated as anonymous and rejected
     • Example:
       • 554 5.3.0 - The user 'anonymous' is not in the email contributor group
  2. Mailbox exists but has restricted sender permissions
     • Only specific users or groups are allowed
     • External or unapproved senders are blocked
     • Examples:
       • 550 5.7.1 Client does not have permissions to send
       • 550 5.7.1 Unable to relay
       • 554 5.7.1 Access denied
  3. Mailbox does not exist (invalid or inactive address)
     • Email address is incorrect, deleted, or not provisioned
     • Examples:
       • 550 5.1.1 User unknown
       • 550 5.1.1 Recipient address rejected
       • 554 5.1.1 No such user
  4. Mailbox exists but is unavailable or misconfigured
     • Mailbox cannot receive emails due to:
       • Disabled mailbox
       • Quota/storage capacity
       • Backend configuration problems
     • Examples:
       • 554 5.2.0 Mailbox unavailable
       • 550 5.2.1 Mailbox disabled
  5. Mail flow or security restrictions
     • Messages are blocked by:
       • Transport rules
       • Security gateways or spam filters
       • Connector or relay restrictions
     • Examples:
       • 550 5.7.1 Message rejected due to security policy
       • 550 5.7.1 Sender not authenticated
  6. Suppression list (secondary effect)
     • When any of the above scenarios returns a 5.x.x permanent failure:
       • The sending infrastructure (e.g., Amazon SES used by SAP) classifies it as a hard bounce
       • The recipient address is automatically added to a suppression list
       • Further emails to the same address are blocked
     • This is reflected in SAP Service Cloud Version 2 as: Permanent - OnAccountSuppressionList
     • The suppression list is not the root cause, but a result of previous delivery failures.

1. Fix recipient-side issue:
   • Ensure the mailbox (where applicable): 
     1. Exists and is active
     2. Accepts emails from external senders
     3. Allows the sending system or domain
   • Review (where applicable): 
     1. Mailbox permissions
     2. Distribution group restrictions
     3. Application mailbox configuration
2. Review mail flow and security settings:
   • Check:
     • Transport rules
     • Connectors
     • Email security policies
   • Ensure external emails are not rejected
3. Validate with testing
   1. Send a test email from an external account to: test@example.com (the same email that got bounced)
   2. Confirm successful delivery
   3. Check if the bounce is still present
4. Remove the offending email from suppression list (if/when applicable) 
   • After resolving the root cause:
     • If using SAP default MTA (Amazon SES):
       1. Open an SAP support case
       2. Request removal from the suppression list
     • If using customer-managed MTA:
       1. Contact internal IT / email infrastructure team
       2. Remove the address from the suppression list
     • ⚠️ Do not remove suppression before fixing the root cause, as the suppression may be retriggered. 

• Refer to KBA: 3433341 - Resolving Outbound Email Blocking Issues in Service Cloud V2
• Configure Emails

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