On 5/6/23 17:28, H via mailop wrote:
I am new to doing mass mailings to customers and leads - not spam - and am looking for some introduction how to interpret different types of rejection messages so we can improve our success rate etc.
Many mailbox providers do at least some things "their own way" so there's no catch-all one-stop for all messages and codes. But a good start for what the different status codes (should) mean is https://www.iana.org/assignments/smtp-enhanced-status-codes/smtp-enhanced-status-codes.xhtml
SMTP error from remote server for RCPT TO command, host: xxx.mail.protection.outlook.com (104.47.51.202) reason: 550 5.7.1 Service unavailable, Client host [74.208.4.197] blocked using Customer Block list AS(1420) [AM7EUR03FT040.eop-EUR03.prod.protection.outlook.com 2023-05-05T06:31:14.035Z 08DB4D3079BE1687]
That IP is in at least 15 blacklists: https://multirbl.valli.org/lookup/74.208.4.197.html
As others have said: If you share your outbound IP with others you share your IP reputation with others. So you will get penalized because your neighbors are spammers. Self hosting is not necessarily the cure for this though as (especially with the "too big to fail" crowd) there might instead be _too_few_ mails coming from your IP to build a reputation which might impact your deliverability to inbox.
-- BR/Mvh. Dan Malm, Systems Engineer, one.com _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
