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When the emails is sent to gmail its being blocked stating
Delivery has failed to these recipients or groups:
___@___.___ (***********@gmail.com)
Your message wasn't delivered because the recipient's email provider rejected it.
all my records are up to date..
gmail.com suspects your message is spam and rejected it.
| natasha.daniel | Office 365 | gmail.com | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sender | Action Required | |||||||||||
| <br> | --- | --- | --- | --- | --- | |||||||
| Messages suspected as spam |
| How to Fix It |
|---|
| Try to modify your message, or change how you're sending the message, using the guidance in this article: Bulk E-mailing Best Practices for Senders Using Forefront Online Protection for Exchange. Then resend your message. |
| If you continue to experience the problem, contact the recipient by some other means (by phone, for example) and ask them to ask their email admin to add your email address, or your domain name, to their allowed senders list. |
Was this helpful?Send feedback to Microsoft.
More Info for Email AdminsStatus code: 550 5.7.350
When Office 365 tried to send the message to the recipient (outside Office 365), the recipient's email server (or email filtering service) suspected the sender's message is spam.
If the sender can't fix the problem by modifying their message, contact the recipient's email admin and ask them to add your domain name, or the sender's email address, to their list of allowed senders.
Although the sender may be able to alter the message contents to fix this issue, it's likely that only the recipient's email admin can fix this problem. Unfortunately, Office 365 Support is unlikely to be able to help fix these kinds of externally reported errors.
Original Message Details
| Created Date: | 3/2/2023 11:29:38 PM |
|---|---|
| Sender Address: | *********@*****.com |
| Recipient Address: | *********@gmail.com |
| Subject: | Email check |
Error Details
| Reported error: | 550 5.7.350 Remote server returned message detected as spam -> 550 5.7.1 [2a01:111:f403:700f::715 19] Our system has detected that this;message is likely suspicious due to the very low reputation of the;sending domain. To best protect our users from spam, the message has;been blocked. Please visit; https://support.google.com/mail/answer/188131 for more information. c23-20020aa7c997000000b004ace5dc6b61si945041edt.369 - gsmtp |
|---|---|
| DSN generated by: | PN3P287MB0113.INDP287.PROD.OUTLOOK.COM |
Using Classic Outlook on Windows for personal email, calendar, and contact management
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
The issue now appears to be the requirements by Gmail/Yahoo, to have DMARC records published in DNS for your domain.
https://dmarcian.com/yahoo-and-google-dmarc-required/
Once you add the dmarc records in, your email should begin being delivered.
** Update **
The original issue of emails sent via O365 Exchange to Gmail and Yahoo not being delivered was a pre-cursor to them requiring changes to DNS.
If you did not have a DMARC record published for your sending domain, you were affected and your email stopped. When this first started and was not widely known that they made those changes, it was possible to force O365 Exchange email to be routed thru an SMTP connector.
However, now that the requirements have been published by them and "well known" , all that needs to be done is add a DMARC record into your domains DNS. (SPF and SenderID records should already be in there)
https://dmarcian.com/yahoo-and-google-dmarc-required/
Michael B. Morell, CISSP #431307 CCSK (he/him/his/sir)
DirectionWeb
Owner and Information Security Professional
Hi Joshua
It sounds like the issue you had was specific to the incorrect SPF record; where spammers were able to send as your domain. That caused you to get flagged by gmail.
The "true" root cause for everyone else, was because of google/yahoo requiring DMARC records published in DNS. They began enforcing it BEFORE they published the requirements. Which sent the O365 email sending world into a frenzied death spiral.
At first, creating a new SMTP connector and routing it directly into gmail seemed to "fix" the issue. As it seemed like gmail was having issues with IPv6. But that "fix" was just a temporary band-aid. Because the "real" solution was to add a DMARC record. (I myself was affected because when I migrated from my on-prem BIND servers over to godaddy dns a few years ago; I forgot to add in a dmarc record and never fixed it, until now)
With that said; your issue (and possibly others) was SPF. The rest of the herd, is DMARC related.
On that same note, if anyone is reading this; also enable DomainKeys and DKIM for your domain. This is how you set it up in O365.
Michael B. Morell, CISSP #431307 CCSK (he/him/his/sir)
DirectionWeb
Owner and Information Security Professional
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It sounds like the issue you had was specific to the incorrect SPF record; where spammers were able to send as your domain. That caused you to get flagged by gmail.
Yup. Invalid or missing SPF resulting in spammers spoofing his domain name to spam others. I have been monitoring all posts about this issue (Yahoo/Gmail bounce backs) and not all of them are DMARC related. Some have multiple SPF records which causes it to "break" or become invalid. Most of them do not have both or all records (SPF, DMARC, DKIM).
Hi Guys,
Just to be clear, if you find yourself in this situation
a, The email from Google shows the rejected headers, in these headers
i. The source address is an IPv6 address.
ii. The rejection headers indicate that the email source address could not be validated against your SPF
If the above is true for you, then you may be experiencing the issue where a MS IPv6 address is not being resolved correctly as a MS email server.
If you want to confirm this is the case for your, grab the source address from the email headers, perform a IPv6 reverse lookup, if it doesn't resolve to *.protection.outlook.com, then you have the source address issue.
This causes Google to mark the email as being spoofed and you will get the rejection. The wording on the email response from Google is slightly misleading.
If this is your situation, creating connectors to force Microsoft to send the emails using IPv4 will resolve the issue, because the IPv4 address seem to resolve correctly.
Absolutely important to have SPF and DKIM setup correctly, I do recommend to do that first to make sure these are correct, if you still have the issues then try using connectors.