Some emails sent to my instance are not being received

[myles3]

My instance is using the default ServiceNow email address. It is able to receive most email, that then shows up in Email System Logs, but one particular message is consistently ignored. This occurs both on my development and personal development instance. The email is sent by a Microsoft Exchange plugin, Symantec Web Email Protection, but the headers don't look much different than other messages (included at bottom, if relevant). The same message is able to be received by other email providers, such as gmail.

I've confirmed that the email is being sent and accepted by ServiceNow servers (does not return failure message), but it never shows up in Email System Logs or changes the Last Email Received timestamp. I've tried blanking all Ignore/Discard incoming email properties. I do not have the Email Filtering plugin activated.

Does ServiceNow do any sort of filtering on inbound email that could explain a message being silently rejected? What else might be happening with these missing emails?

Anonymized Headers:

DKIM-Signature: v=1; a=rsa-sha256; d=<removed>; s=<my email domain>; c=relaxed/simple;

  q=dns/txt; i=@<my email domain>; t=1452108928; x=1467660928;

  h=From:Sender:Reply-To:Subject:Date:Message-Id:To:Cc:MIME-Version:Content-Type:

  Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From:

  Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id:

  List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive;

From: "My name" <my email>

To: <myinstance@midatl.service-now.com>

Subject: Secured Message

MIME-Version: 1.0

Content-Type: multipart/mixed; boundary="SECURITY_WM_MAIL"

Message-ID: <20160106193527.AC6584070001@<my email domain>

Date: Wed, 6 Jan 2016 11:35:27 -0800

[Dub Myers · Accepted solution]

The ServiceNow email infrastructure will not pass an email through to the instance if it exceeds the email infrastructure size limit. Your instance would have no record of this since it is blocked at the inbound email server.   Could this be the case for this email?

Otherwise, all email is should be delivered to the instance, leaving it up to the administrator to set ignore/process functionality.   (This is true even in the case of spam email, ServiceNow does perform spam scoring, and inject headers into the email indicating the presence of spam or a virus.   But you must configure your instance to ensure email with those headers is ignored.)

If the Email Filters   plugin is not active, then the email properties apply, which you have said you are blanking out:

• glide.pop3.ignore_headers
• glide.pop3.ignore_subjects
• glide.pop3.ignore_senders

Also, you should check the instance's system log to see if something more catastrophic occurred while trying to read the email.   In that case, something might be logged, but no email record would exist due to errors while reading.

[myles3]

The email size does not exceed 1MB and there are no email-related errors in the System Log. However, the statement that "Otherwise, all email is delivered" does answer my question.

[myles3]

Just want to note that we eventually did figure this out. The problem was that there was an error in mail encoding headers. ServiceNow rejects email messages with this type of encoding error.

One of the multi-part headers was:

Content-Transfer-Encoding: 8-bit

While the correct encoding would be:

Content-Transfer-Encoding: 8bit

[mark141230]

I know this is old but I have the same issue like this, would like to know how did you resolved it