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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...
timbertens this problem is occurring since last Tuesday! Our mail server is Zimbra ZCS, and we have approximately 1200 accounts, that can't send mails to MS 365 Exchange... We are having some troubles and loss with this 😕
Yes started last Tuesday for me too. First time I knew about it was 7:30am GMT.