Message of rejection: unauthenticated account

Dear Mònica Juncà,

Good day! Thank you for posting to Microsoft Community. We are happy to help you.

Based on your description, I understand that you're experiencing issues with sending emails due to authentication errors. This is a common issue when SPF (Sender Policy Framework) or DKIM (DomainKeys Identified Mail) is not properly set up for your domain.

To resolve this, you'll need to authenticate your email account with SPF and DKIM. To authenticate your email account with SPF (Sender Policy Framework) or DKIM (DomainKeys Identified Mail), you'll need to follow these steps:

♦Setting Up SPF

1. Log in to your domain registrar or DNS hosting service.
2. Create an SPF Record:
   • Add a new TXT record to your DNS settings.
   • The value of the TXT record should look something like this: v=spf1 include:_spf.google.com ~all. This example allows Google to send emails on behalf of your domain. Refer to Set up SPF identify valid email sources for your Microsoft 365 domain - Microsoft Defender for Office 365 | Microsoft Learn.
3. It might take some time for the changes to propagate.

♦Setting Up DKIM

1. Generate DKIM Keys.
2. Add DKIM Record to DNS. To set up DKIM record, please refer to How to use DKIM for email in your custom domain - Microsoft Defender for Office 365 | Microsoft Learn.
3. Go back to your email service's admin console and enable DKIM signing for your domain.

♦Verifying Your Setup

• SPF: Use tools like MXToolbox to check if your SPF record is correctly set up.
• DKIM: Send a test email to a service like DKIMValidator to ensure your DKIM signature is working.

For more detailed instructions, please contact Microsoft support through the Office 365 admin portal by going to Office 365 Admin Center (Admin permission is needed) > Support > New Service Request. The support engineers there have the correct escalation channel, and this is the most efficient way to report such issue. You can refer to Get support - Microsoft 365 admin | Microsoft Learn.

Thank you for your cooperation and understanding. Please understand that our initial response may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution. Thank you for your cooperation.

Hello Mònica Juncà,

Good day!

We are following up this thread to see if you have further concerns on this topic, or if you have any other questions. If our information was helpful, we also invite you to vote the reply so that others may find it easier.

Thank you for your time and wish you a nice day.