Forum Discussion
Trying to find help for 550 5.7.511 Access denied, banned sender
I run a mail server for many business clients of mine. Microsoft have blocked our IP address, so we cant send to Office365 email addresses. I get a bounce back saying: host cr-studio.mail.protec...
Hi all,
This problem may have been solved after the above messages, but it's recurred now, and I have two items of information I've learned so far in this subsequent bout which I wanted to share:
1) They are listing entire address blocks, so your individual IP address does not appear in their blocklist database. So then the automatic tools say that you're not blocked because you're not in the database. They're wrong, obviously, but this seems to be why.
2) That "frontbridge" stuff is some internal microsoft e-mail software objecting to your "Content-Type: message/delivery-status" e-mail header, or at least it seemed to be in my case. Be less correct about the e-mail headers (make it plain text) and I think you will not encounter this problem.
regards,
ajr
This problem may have been solved after the above messages, but it's recurred now, and I have two items of information I've learned so far in this subsequent bout which I wanted to share:
1) They are listing entire address blocks, so your individual IP address does not appear in their blocklist database. So then the automatic tools say that you're not blocked because you're not in the database. They're wrong, obviously, but this seems to be why.
2) That "frontbridge" stuff is some internal microsoft e-mail software objecting to your "Content-Type: message/delivery-status" e-mail header, or at least it seemed to be in my case. Be less correct about the e-mail headers (make it plain text) and I think you will not encounter this problem.
regards,
ajr
