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Home > Communications > Bulk or Mass Emails: Best Practices
Bulk or Mass Emails: Best Practices
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Communicating with large groups or lists of contacts requires a more focused approach to the message- both in content and delivery. And when using GrowthZone as your communication provider, you need to be doubly aware! Transgressions on the part of one customer affect ALL GrowthZone subscribers, as there is a shared pool of email servers in use; when one gets flagged for a violation, it affects ALL customers using that server pool.


Here are some detailed recommendations to help avoid being flagged as spam and/or avoiding being filtered out by firewalls and servers.


  1. Text to images ratio. Messages that are over 40% images do generally get flagged with a higher spam score, contributing to messages ending up in recipient's junk mail or being caught by firewalls. You can test your text-to-image ratio using this tool.
  2. Missing Alt Text tags. Adding details to the alt text field of an image helps improve spam scores, indicating that your message is making an attempt to follow ADA guidelines. Here are some excellent Alt Text suggestions.
  3. Active Email List Management. Just like database maintenance, Email List Management is not a destination- it is a journey. GrowthZone provides multiple reports and actions to assist in keeping your email lists up to date and as clean as possible.


Email List Management Tips

Email list management is the best regular task that anyone can do to keep their email-sending reputation high which increases the chances of an email making it into the Inbox of the intended recipient. Removing those who no longer want to receive your emails, updating outdated email addresses, and reaching out to get corrected addresses is a something that should be done on a routine basis.


Below are steps you should take after sending out a mass email to keep your email list up to date.


  1. Check Email Delivery Stats of your mass email.  Find your email in the Communication module on the Browse tab. Click the ... in the Actions menu in the row of your mass email. Click Delivery Stats. See more about the Email Delivery Stats screen.
  2. View Delivery Failures (Soft Bounces and Rejections). Soft Delivery Failures that remain 3-4 days after a mass email has been sent should be evaluated error by error to see if these are errors where someone is marking this email as spam. See the FAQ on rejection errors below for ideas on what to look for.
  3. Download the Soft Bounces and Rejections list and act on it. Click the download icon in the top right corner of the Soft Failed Communication Details window. Use this downloaded list to reach out to them or as a check list of who to remove them from your list.
    Tip! The downloaded list creates a handy call list for you. It contains the contact's phone number and other possible email addresses on their contact record to make it easier to reach out to them.




Other Cleanup Tips to Improve Engagement

GrowthZone automatically marks hard bounces as invalid for you because these emails are definitely not making it through. We also do not attempt to send to contacts on your recipient list that do not have an address, are set to 'Do not contact', or are duplicates. So from an email reputation standpoint, nothing more needs done with these contacts, however, the state of these contacts mean that your contacts may be missing out on receiving your communication. Spending time to update these to better, confirmed email addresses will improve their engagement with your association.


Check these additional locations for addresses that might need your attention. Once you've located the email addresses on these lists, reach out to these contacts and get updated email addresses from them or remove from your mailing list.


  1. View Delivery Failures (Hard Bounces) on the Email Delivery Stats.
  2. View "Removed Due to Flood Protection, Invalid, Do Not Contact, or No Email Address" on the Email Delivery Stats.
  3. Review addresses on the Invalid Email addresses Report to see a list of everyone with invalid addresses in your entire database! Filter to the most recent marked as invalid to start with your most current customers. Old email addresses marked invalid may just be able to be deleted.


Additional Recommendations

  • Segment your list of active members from non-members, and even further into smaller groups as much as possible. Sending to these groups separately will help if further tracking of issues have to be done.


What is GrowthZone doing to help?

GrowthZone continually checks to make sure that who you send to is not getting us put on black lists, such as the SORBS list.  If you send out an email that puts us on a black list, then most likely somewhere in your email addresses there is an email address that is a spam trap (known as a "honeypot"). Email checking programs or the delivery failure report cannot tell you if they are valid or not (that is why they are a trap!). Black list owners will buy/signup for an address where they specifically do not subscribe it to any lists and if they get an email, they know it was unsolicited. That is just one of many ways they do this.

GrowthZone will only know the date and time and sending domain of the email that caused the listing (yours or other customers). We can generally match the date and time of the listing to the email message that caused it. However, the date and time can also be the date and time that a previous email was sent and is now retrying (usually a few days after the original email was sent). It can be difficult to know exactly where the black listing is coming from– which is why the best practices are to keep up on good mailing list management and know that your lists are made up of real people who are expecting emails from you.  Having lists segmented and sending separate emails to smaller groups could point to the culprit, if one exists.


What we do know is if we find an entry in a black list due to an email from your domain, there may not be any other way to get out of that issue without totally removing lists. We have ability to track which list was sent to at which time so we know the offending list. If you have your list segmented into smaller groups and send those at different times might lead us to be able to wipe out a smaller list should this happen.


Q. Why does the Email Delivery Stats screen have different numbers today for soft bounces than it did yesterday?
A. After an email is sent, certain bounced emails are retried several times. As those emails become successful, the bounced count is reduced on this screen. Note that the Email Delivery Failures report will report those bounces and will not be cleared out of the report. So looking at the Email Delivery Stats three to four days after the email is sent, is the best place to look for the final list of soft bounces.


Q: Is it OK to delete an email address of one that is marked as invalid?
A: Yes, adding an email address that was once marked as invalid will continue to retain that invalid status if re-entered into another contact.


Q: Why don't I need to look regularly at the Hard Bounces?
You certainly can actively reach out and make corrections to any of these, but these addresses are no longer damaging your email reputation because GrowthZone automatically marks hard bounce emails as invalid.

Q: Is it ok to remove or delete contacts that you no longer want?
A: Not usually. We don't generally recommend deleting contacts- ESPECIALLY if there is additional historical data such as event registrations, payments, membership history, etc. attached to the record! However, deleting an email address for that contact that is causing issues is perfectly acceptable.


Q: What do the various Rejection errors mean when looking at the Soft bounces?
A: Rejections: these can vary in why they occur, but often are due to the recipient viewing you as a spammer. These errors come from the ISP (Internet Service Provider) and there is not a standard message to look for, however here are some examples:

    550 - 550 Rejected by header based manually Blocked Senders:

    550 - 550 Envelope blocked

    550 - 550 Envelope blocked - User Entry

    550 - 550 we do not accept mail from this address

    550 - 550 blocked



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