How to fix a 550: 5.7.515 Access denied error

Hello Dennis. The message "550 5.7.515 access denied" signifies that Microsoft Outlook.com (including Hotmail, Live.com, and MSN) is rejecting your email due to the domain being utilized not meeting the authentication requirements. This relates to Microsoft's new policy regarding high-volume senders - domains that are sending 5,000+ emails per day to Microsoft consumer services. In order to protect users from spam and phishing Microsoft now has more enforcement and will require that for you to send emails to Outlook.com, your domain must pass SPF and DKIM both have a valid DMARC policy that guides back to the domain in your From field.

To resolve the problem, you or your domain admin will need to do the following:

• Publish an SPF record that includes all sending servers.
• Configure DKIM signing and publish the Public Key in DNS.
• Set up a DMARC Policy (v=DMARC1; p=none) aligned to SPF or DKIM.

Here's the full article: https://support.microsoft.com/en-au/topic/fix-ndr-error-550-5-7-515-in-outlook-com-34cfe8f8-6fbf-457e-9e8b-9e4dbaf4e0ef

Best regards,

Hello Dennis. Thanks for getting back. I know it is frustrating to find yourself in this circle. The error 550 5.7.515 Access denied is triggered when Microsoft blocks emails from a domain (like Yahoo) because it failed authentication (SPF, DKIM, or DMARC) checks. When it comes to authentication checks, your Yahoo email is on the receiving side and not the sender side of a process involving DNS settings and authentication (SPF/DKIM/DMARC) checking Microsoft verifies to determine if Yahoo is authorized to send email on your behalf.

Now, because you are using a personal Yahoo email account, you do not have access to authentication records (your domain and all related settings belong to Yahoo). Therefore, the only entity that can update or configure the required DNS settings on the Yahoo domain to meet Microsoft's requirement is Yahoo itself.

Unfortunately, Microsoft will not bypass this block manually for every user, and Yahoo probably won't adjust domain-wide authentication settings for personal accounts. This is why both providers have avoid responsibility: Microsoft is enforcing a rule, and Yahoo owns the domain but doesn't let individual user control this level of granularity.

Your best option would be to:

Use another email provider (outlook.com or Gmail) to send messages to Microsoft's domains.

Or, if you have a custom domain (i.e., yourname.com), you can configure your own SPF/DKIM/DMARC using your domain host.

Best regards,