Forum Discussion
Failed to send emails to outlook/hotmail recipients, returns error 550 5.7.515
-- Recently, our mail server got large amount of bounced back emails
As far as I know the new mass mailer policy was put in place April 2025. Not sure why you are just now seeing the impact.
-- that it's because of the requirement of SPF (Pass), DKIM (Fail) and DMARC (Pass) authentication
Part of High Volume Policy and also in Anti-phishing policies
https://learn.microsoft.com/en-us/defender-office-365/anti-phishing-policies-about
-- Any way to contact hotmail/outlook/live/msn postmaster?
https://substrate.office.com/ip-domain-management-snds/postmaster/
Help needed too with the 550 5.7.515 error. Received a message from my meanwhile previous provider that my mail-account was used to send spam, that a 'problem' occured with their server and a 'corrupted' backup. All happened without my knowledge.
Moved to another provider. Problem seems solved. I can send to personal Microsoft accounts again for example. But business clients that have hosted their e-mail at Microsoft still can't receive my mail although my new provider says that they are delivered.
An error message isn't received anymore. Putting my account on the 'safe mail' list doesn't help (as read in the article above).
We're groping in the dark now; does someone have an answer?
Lots of thanks in advance!