Office 365 tenant not receiving SMTP emails

John Davies
John Davies used Ask the Experts™
on
HI ,
I have configured a SMTP site on a Virtual machine. I am using Database mail from sql server to send a test email. I can send an email to my yahoo address successfully. However the send test mail is not working for a Office 365 email address.
The sysmail event log shows status of mail as sent in the msdb database.
On office 365 there is nothing in the Quarantine or mail flow restrictions either.

Cheers

john
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Most Valuable Expert 2015
Distinguished Expert 2018
Commented:
Any O365 address? Or just the ones in your tenant? What's your current configuration, do you have on-prem Exchange servers, what kind of object you have for the address on-prem and where is the MX pointing at? And how are you sending the messages, is it a direct send or via SMTP relay (the different methods are detailed here: http://technet.microsoft.com/en-us/library/dn554323.aspx)?

You can run a message trace to check whether the message actually hit the EO servers: https://technet.microsoft.com/en-us/library/jj200712(v=exchg.150).aspx

Author

Commented:
Hi Vasil,

Without testing all email address Vasil it seems as though it is just test mails to our tenant which is weird as they worked the other day and we have made no changes.

There is no on-prem servers, everything is cloud, the set up is in Azure and we have just set an SMTP service without office365 relay.

We are not using office365 to send email.

What is direct send?

As for the message trace i did not find anything relating to the email.

Have checked the trace also and they do not exist in there, weird as they are getting sent to a test Yahoo account.

Ta

John
Adam BrownSenior Systems Admin
Top Expert 2010
Commented:
Are you using the same domain name in the FROM: field on the messages you're sending as the recipients? Because Microsoft black-holes messages that originate from outside O365 that are sent from: an O365 tenant's domain name to: the same domain name. Those are regarded as blatant spoofing attempts and completely dropped by their filters without logging. You would either need to modify the Spam protection settings to allow those messages from your SMTP server's IP address and create a receive connector that directly accepts those messages from your server's IP.
Most Valuable Expert 2015
Distinguished Expert 2018

Commented:
And make sure to add the IP/FQDN of the sending server to your SPF record. You can find details on how to do that in the article I listed above.

Author

Commented:
Thanks guys for your help, both were very helpful. Sorry for delay

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