Not receiving mail from Outlook.com, Office 365 via MS Exchange

#1

Hi,

I set up an MXroute mailbox for a client. The SMTP server is lisa.mxrouting.net.

SpamAssassin is currently disabled.

They are not receiving any email from at least three of their suppliers (either to Inbox, Spam or Junk folders).

Since they also had an alternate Gmail account they provided that to their suppliers and that’s working as a temporary solution so they can continue their business.

I had a look at the headers in the emails from their clients and one sent mail via Office 365 using Word. The others are using MS Exchange.

In each case there are references to outlook.com, e.g. NAM02-BL2-obe.outbound.protection.outlook.com

I also sent an email from a personal Outlook.com account and Cc’d that to my regular email account. I received the email to my regular account but nothing in the client’s Mxroute mailbox.

Mail is received just fine from other sources and also sends OK including to the suppliers.

I have SPF, DKIM and DMARC records set up for the client - though I don’t think that should impact incoming mail anyway.

The client’s domain hosts a WordPress site and tansactional mail is sent from WordPress via the MXroute SMTP server and received at the MXroute account.

The problem seems only to be with Outlook.com / MS Exchange.

If you need to see the headers from the Outlook.com email I sent to my own account, should I paste them here?

#2

Hey friend,

Thanks for reaching out. I found 91 emails in the logs recently that were rejected by “domain_filter” for your domain. A significant number of those were from Microsoft/Hotmail/Outlook. I can’t offer more insight into what specifically triggered this, but this triggers from user configured filters. I hope this helps to narrow it down.

#3

Thanks for the reply and yes it was helpful to narrow things down.

FYI I didn’t realize that SpamAssassin and the SPAM filters are independent.

SpamAssassin had been set to add a prefix and to deliver to the Spam folder (not delete). The first troubleshooting step was to turn off SA.

However, SPAM filters also have a setting for Action to perform on the identified spam which I had inadvertently set to delete. Once I changed that to deliver to the Spam folder I could see that the word filters I was using in the SPAM filters were triggering the mail from Outlook dot com to be sent to the Spam folder even though the email content had none of the trigger words (unless it uses a fuzzy match and the word “sales” is grouped somehow with the trigger word “marketing”).

I removed all of the SPAM filters and the mail from Outlook dot com now goes to the inbox.

The next step will be to enable SpamAssassin and see if that will work to reduce spam and still allow the Outlook.com emails. I’ll combine this with whitelisting and include the client’s suppliers’ domains.

Pointing out to me that it was the user configured filters triggering the rejection was the clue.

Thanks Jarland!

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