OpenSRS Hostedemail Spam and Rejections Guide

We've recently switched from a third-party service to something in-house to address the demand for better spam protection. With the practical benefit of meeting a better spam-free email environment, this change also affords us quicker turnarounds for new features, stability, closer alignment with our Acceptable Use Policy (AUP), and better outbound IP protection from external blocklists.

Our development team is hard at work implementing a new feature to the new spam solution that will intelligently adjust spam policies based on everyday user interaction with our hostedemail product.

Troubleshooting guide

Ensure the user's domain's MX records are correctly configured based on the cluster.
  • Cluster A: mx.domain.tld.cust.a.hostedemail.com
  • Cluster B: mx.domain.tld.cust.b.hostedemail.com

Make sure the user does not reject, but instead, lets it pass to the spam folder.

 
Ensure that the user is not blocking the sender's IP/domain.
  1. Check the user's block list and webmail filter settings.
  2. You will want to verify that the recipient is blocking neither the sending IP, IP range, domain, or user sending IPs can be obtained from User X's received message headers at the end of the 'Received-SPF' line.
Check whether sender Y's DMARC, DKIM, and SPF policy match user X's mail headers.
  1. Identify the sending IP, and see whether you can identify the IP within the SPF TXT record of the sending domain. This online tool might make things easier.
  2. Check the headers to identify whether the DKIM validation passed. The result is on the 'X-HE-DKIM-Result' line of the header data.
  3. Check the sending domain's DMARC policy. If the DKIM or SPF validation failed, the policy could explain why the sender's message was marked as spam or rejected.

Customers cannot send email

To better troubleshoot these issues, we must distinguish between an SMTP reject, and a bounce reject.

An SMTP rejection happens when the user's email client or webmail produces a notification indicating it can't send. This notification means that we are not allowing the message to go out.

A bounce-reject is when the user sends the email and later discovers a notice in their inbox. The bounce advises that the system didn't deliver the original message to the recipient. This bounce often means that the recipient's email server rejected the message. Bounce messages contain additional details on the reason for the rejection.

SMTP reject troubleshooting

Validate User X's status and sending capabilities

  • Is the user disabled/suspended? 
  • Is SMTP/Webmail Send disabled on the user account?
  • Did the user reach their maximum daily outbound mail ceiling?
Ask your user to save a draft of the message and review it yourself.
  • Could the contents/size of this message's contact list be considered spam behaviour by a recipient?
  • Does this message meet the terms of our Email AUP?

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Bounceback reject troubleshooting

Ask the user for a copy of their auto-generated bounce message. The recipient email server, at its discretion, often provides a reason why they've rejected the sent message. The reason is a chance to self-serve and correct the problem.

Common reasons for rejection include:

  • The recipient does not exist
  • The recipient's mailbox is full
  • The sender did not pass SPF, DKIM, or DMARC policy check
  • The sender's IP is blocklisted
    • For this scenario, advise our support team. Depending on the address and list, we may arrange to have our IP delisted.

Email client rejection errors

We continue to make improvements to our spam filtering solution. Specifically, we've made recent updates on scoring outgoing mail as spam. This change results in cases where email users using specific email clients, such as Outlook, receive a rejection error such as "recipients do not exist" when sending. 

We've confirmed this error message is due to an error/misconfiguration with the email client: we don't consider the rejection a Hostedemail issue.

Support recommends reviewing the email client and configuration; support cannot override this error or troubleshoot third-party email applications.

Marking an email as spam

Marking an email as spam reports various elements of the email like the sender, email headers, email contents, etc. to the email server. The spam filter will incorporate these elements and filter out future emails that are similar.

Reporting legitimate marketing emails as spam will be ineffective since they are considered a trusted sender. Unsubscribing from their mailing list will prevent future marketing emails.

Note: Marking an email as not spam will teach the spam filter which kinds of emails are considered safe.

  1. Mark the email as Spam.
    Hosted_email_mark_spam_email.png
  2. Press Accept to confirm the selected email as spam.
    Important: If you confirm to share your data with our Spam partner, the pop-up will go away and you will not be prompted to make a selection going forward. Should you choose to decline, when you mark an email as Spam, the pop-up will appear each time.
    hosted_email_spam_consent.png

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Additional troubleshooting

If you are still struggling to determine the reason for message delivery failure, please email support.

For every troubleshooting case scenario, please provide:

  • Your reseller ID (the name of your account at signup)
  • Your authorized user ID (what you use to login to manage.opensrs.com)
  • The recipient's email address
  • The sender's email address
  • The date, timestamp, and timezone of the failure

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