Email provider · 5.x.x permanent failure
Every SMTP 554 response on record from Outlook (hotmail.com, outlook.com, msn.com, live.com), with the verbatim text, the enhanced status code, a severity rating and a plain-English fix.
The transaction failed with no more specific reason offered. In practice the receiver is saying the message is unwanted: a spam verdict, a blocklisted IP, or a policy rejection. The accompanying text is where the detail is.
smtp;554 5.2.122 The recipient has exceeded their limit for the number of messages they can receive per hour. For more information go to http://go.microsoft.com/fwlink/?LinkId=526653. (#) [outlook.com]
You are sending to this receiver faster than it will accept from your IP or domain, and it has stopped taking the message. Cut the send rate, spread volume over a longer window, and requeue.
Provider documentation
smtp;554 5.2.121 The sender has exceeded the limit for the number of messages they can send to this recipient per hour. For more information go to http://go.microsoft.com/fwlink/?LinkId=526653. [#.prod.outlook.com #]
You are sending to this receiver faster than it will accept from your IP or domain, and it has stopped taking the message. Cut the send rate, spread volume over a longer window, and requeue.
Provider documentation
The transaction failed with no more specific reason offered. In practice the receiver is saying the message is unwanted: a spam verdict, a blocklisted IP, or a policy rejection. The accompanying text is where the detail is. At Outlook, it is a permanent rejection, and the specific reason is in the enhanced status code and message text of each response below.
Match your bounce text to one of the responses below and follow its guidance. Recipient-side wording means fix the address. Authentication or reputation wording (SPF, DKIM, DMARC, blocklist) means fix your sending setup, and check Outlook's postmaster documentation.
