2,310 questions
Who owns ecelerity? I would contact them to see why these are being generated.
Email bounce backs -><Mailer-Daemon@m***********************************"
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Timothy D. Watson
0
Reputation points
I have two users in my environment who've been experiencing bounce backs from two email addresses who no longer have an account in our online hybrid environment. Below is an error message for one instance. Both errors are similar - but have different addresses:
Exchange | Hybrid management
{count} votes
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Aholic Liang-MSFT 13,886 Reputation points Microsoft External Staff2023-02-21T08:04:33.6466667+00:00 Hi Timothy D. Watson ,
Kindly note that since this is a public forum, in order to protect your privacy, I have hidden your personal information in your posts for privacy reasons.
Thanks for your understanding and do not forget to hide your personal information in your post.
Do you mean these two NDR emails are returned in response to a message to the specified team?
Is this specified team's mailbox a distribution group mailbox? Or a normal user mailbox?
If it is a distribution group, check whether the group contains mailboxes in the NDR.
If the above is not your case, or I misunderstood anything, please correct me so that we can better understand to help you further.
Thank you very much for your patience and cooperation.
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Aholic Liang-MSFT 13,886 Reputation points Microsoft External Staff
2023-02-28T05:15:51.69+00:00 Hi Timothy D. Watson ,
Hope things are going well. I am waiting to see if the above information helps. If there's anything else we can help, feel free to let us know.
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3 answers
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Andy David - MVP 157.8K Reputation points MVP Volunteer Moderator2023-02-20T16:11:08.3033333+00:00 -
Timothy D. Watson 0 Reputation points
2023-02-20T16:59:20.3066667+00:00 I believe Ecelerity is a generic response to a blocked/bounce back email.
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Timothy D. Watson 0 Reputation points
2023-02-20T17:02:56.9733333+00:00 Ecelerity is a generic response to bounce backs.
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Andy David - MVP 157.8K Reputation points MVP Volunteer Moderator
2023-02-20T17:06:30.0866667+00:00 Sorry, what I meant was is generating these? That ecelerity refers to the configuration.
Prob back scatter:
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Timothy D. Watson 0 Reputation points
2023-02-20T17:32:43.7366667+00:00 The user(s) are submitting a "reply-all" to a ticket formed in Zendesk to another team within our organization. I can see back scatter being the culprit, but then I find myself asking, "how would this be an issue if these users aren't in our organization anymore?"
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Andy David - MVP 157.8K Reputation points MVP Volunteer Moderator
2023-02-20T18:14:53.1133333+00:00 With Backscatter, those senders are being spoofed and then its bouncing back to the return-path, i.e. your mail system.
There is not much you can do to stop it 100%, but it is important to ensure you have DMARC. DKIM and SPF set correctly and set to reject for DMARC. This will go a long way to stopping this and help mitigate it.