3675923 - Intermittent Email Failures issue in Microsoft office 365.

Even with a properly configured or valid DKIM record, emails are still being rejected due to a DKIM failure.

SAP Cloud for Customer

1. Send an email from SAP Cloud for Customer.
2. Observe that DKIM fails for some emails, while others are successfully delivered.
3. Resend the failed email and observe that it is successfully delivered upon retry.

• The issue is caused by a DNS timeout during email check on the recipient system, resulting in the "no key for signature" error.
• The recipient system takes more than 60 seconds to verify DKIM signatures, causing intermittent failures despite correct DKIM and DMARC configurations on the sender's side.

The issue occurs due to intermittent failures in DNS resolution or authentication checks (CNAME, SPF, or DMARC) when emails are sent from C4C. Even if the customer has correctly maintained the DMARC, SPF, and CNAME records, temporary DNS verification delays may cause these authentication checks to fail occasionally.
 
When this happens, the system may incorrectly display that SPF or DMARC verification has failed, even though the actual failure is with the CNAME record.
 
Steps to Validate and Resolve:
 
1.Ask the user to retry sending the email.
 
If the email goes through successfully after a retry, the issue is temporary and caused by DNS resolution delay.
This indicates that domain authentication (SPF/DMARC/CNAME) and IP configuration are correct.
 
2.If the failure occurs consistently on every attempt:
Validate that the domain’s CNAME record is correctly configured.
Confirm that SPF and DMARC records are maintained as per Microsoft’s requirements.
 
3.If the issue persists intermittently:
 
This is a known issue with Office 365 related to DNS verification timing.
The customer should reach out to Microsoft Support for further investigation and assistance.

• Refer to: SAP Note 3424159 - Enabling DMARC Configuration

DKIM failure, DKIM error, no key for signature, DNS timeout, email delivery issue, DMARC setup, intermittent email failure, email authentication, email bounce error. , KBA , LOD-CRM-ADM , Administration UI , How To