Email Receipt Issues

When you send email invitations to complete a survey using a contact list or when you send a "test" message, there can sometimes be issues which prevent recipients receiving emails or the messages being moved into their Junk/SPAM folder.

This can apply to any emails sent from the system including Invitations, Email Triggers, Save and Continue mails, and report notifications, although only invitations currently have feedback (in the form of "bounces") that you would be aware of. 

SmartSurvey sends 10s of 1000s of emails every day and we will know about any general issues with the system quickly. You should check the SmartSurvey status page for any listed issues before deciding whether to raise a support ticket. If it is not working and the status page is not showing anything then it is highly likely that the issue relates to either your sending domain settings or the recipient email server.

If you use Mimecast for your email and are sending high volumes of mail to your own users, please see the article on Mimecast whitelisting, which will significantly speed up delivery to mimecast addresses.

Common reasons for delivery delay/failure

  1. Misspelled email addresses, including on some systems where the part before the @ is case-sensitive
  2. Delay in sending caused by SmartSurvey system load or by the receiving system. Except during maintenance, SmartSurvey will send most emails within a minute, usually in a few seconds.
  3. Delays caused by greylisting on the receiving system. This is where high volumes of emails are rejected during the first attempt and accepted subsequently, usually after 1 minute. This is an anti-spam mechanism used by a number of large email providers, especially Mimecast.
  4. Rules that are setup by the receiving system to prevent SPAM, either default rules or those that have been added. For example, a rule might not allow email from "" to originate outside of the receiving email system itself, causing problems if you have verified a Sending Domain. These might show as bounces in your account for an invitation but otherwise will simply be lost. Since we have no visibility or control of this, this can be hard to determine but we can see when an email was sent successfully, in which case, the other end has done something with it.
  5. You have broken your DKIM/SPF DNS records for a Sending Domain, which will fall-back to using our normal "mangling" process, which might break a specific rule you might have used to allow email sent from your verified domain. If you have DMARC applied, this is much more likely to be a problem since DMARC will require alignment of the various parts of the email.
  6. Your message being marked as SPAM. Since SmartSurvey servers are shared, the actions of any customer can affect the deliverability of other customers' emails. It is your responsibility to reduce the risk of your messages being marked as SPAM by ensuring you have a lawful basis for having the email addresses, not keeping them for too long without re-opting in etc. and making it clear why an email is being received. People are less receptive than ever as they are constantly contacted by different companies looking for attention so try and craft your messaging so that people don't press the "Report SPAM" button.
  7. You have added firewall rules for specific SmartSurvey email servers in order to try and lock-down your system*

* We do not recommend or support the use of IP firewall rules to "whitelist" our email servers. Apart from the fact that you should not need to if you are correctly checking for DMARC alignment on received emails, the IP addresses are subject to change at short notice and we do not have a mechanism to update customers when these changes occur.

How can I tell?

If you are sending an invitation (except the test message), it will show any errors that our system has been informed about in the invitation results. These will usually have helpful messages like "Mailbox Full" so you can see what the problem is.

If you see a message like "Suspected SPAM", this could be caused by your specific message being marked as SPAM by a recipient (hence the reason why you must help the recipient to understand why they are receiving something), or it could be caused by a problem with the reputation of one of our mail servers. We will usually notice this but if it happens out of hours, it might not be noticed until the following day.

For emails that are not sent as part of the invitation, we don't currently have an interface for you to know that e.g. exports or email triggers are failing, which is why we recommend testing anything you setup before using it "in production" using your own email addresses. Our system will currently pick up some issues like these which will be raised in a Support Ticket for your attention.

We recommend sending test emails to a gmail account before committing to any large-scale emailing. GMail provides a "Show Original" option on the message which displays the DKIM, SPF and DMARC status of the message very clearly at the top. If these don't pass, it is likely your DKIM setup is incorrect and you will need to raise a support ticket or try another Sending Domain.


SPAM is any "unsolicited" email. that-is, email that was not asked for or expected. Now that email is very widely used, there are three scenarios to be aware of:

1) Genuine SPAM - Someone has illegally (or dubiously) obtained email addresses and is sending email that should not have been sent (or perhaps obtained the email addresses for a different lawful purpose than it is being used for). This is the most likely to be "Marked as spam" by the recipient and can affect any future deliveries from the same email server. SmartSurvey includes an opt-out link but you should be using your own internal mailing lists and these need an opt-out mechanism too, either via SmartSurvey invitation results being manually updated in your system or by another automated system.

2) Email that is considered SPAM - this is where the email is legally sent but the user either does not know why they have received it or it looks suspicious. Some people even use the "Mark as spam" as a way of saying, "I am no longer interested in this" so that the sender is considered suspect even though they did nothing wrong. This can be helped by clear and concise messaging (see below) but in general, the email should not be too short or overly long and can include wording like, "If you no longer want to receive these <emails> then please click here to unsubscribe".

3) Email spoofing - This is where the sending or receiving email servers are not able to verify that the sending system is allowed to send email on behalf of a domain. Any good mail server (including SmartSurvey's servers) are configured to ensure that your domain is treated correctly so this should never be an issue.

To ensure that emails are sent with the best chance of being delivered, it's important to focus on these elements of the message.

The way that suspected SPAM is processed usually consists of checks at 3 places:

1) As soon as the email is sent to the receiving system. If this happens, the error will be processed by SmartSurvey and, in the case of Invitations, will cause the recipient to be marked as "bounced"

2) At an invisible part of the receiving system that can make up its own rules and might or might not apply them correctly or fairly. If this blocks content, an error may or may not be generated back into SmartSurvey. It might also cause a delay before the mail appears in the destination mailbox.

3) As a set of rules that don't prevent delivery but either move the suspected spam into the Junk mailbox or otherwise put a message at the top like "Beware, this email looks like SPAM because..."

SPAM rules are not an exact science and can vary from provider to provider, so this guidance is only to improve your chances of successful delivery, it can never be guaranteed.

Note that modern email servers have many mechanisms, of varying reliability, that can reject or defer email for any number of reasons. If you are configuring security on a receiving server, you should be very careful that you do not use settings that will reject good emails based on a misunderstanding of how email works e.g. the differences between Reply-To, From and Sender email addresses.

Sending Emails and Domains

SmartSurvey allows you to verify an email address to be used as a "from" address in several of the email systems, such as the address book and email triggers. If you use an email and do NOT have an associated sending domain then our system will send on your behalf using one of our own email domains.

If you use DMARC in strict mode, then emails sent from SmartSurvey using a verified domain sender will not align unless you setup a bounce domain that points to the smartsurvey return path (you can set this up in the Domain Sender Settings page).

Contact List

Low quality contact-lists are the most likely reason for your email invitations to fail delivery and they can cause significant reputational damage to SmartSurvey email servers since invalid email addresses or addresses that are seen as dormant for considerable time are markers that your data is not valid or up-to-date.

  • Ensure your contact list data is valid and up-to-date. If your address books contain lots of old email addresses or those that were obtained in an indirect way, it will increase the chances of people using the "Mark as spam" button, which greatly increases the chance of your messages being blocked. Good-practice is to offer people a regular (6 months or yearly) re-opt-in. If people are not interested in your marketing, don't risk your reputation by continuing to send people things. This also helps provide feedback as to whether your marketing is working well enough for people to want to stay opted in.
  • You should proactively review the list to ensure you remain compliant with the Data Protection Act if you are sending to UK Citizens (and are recommended to for others). Specifically, ensure that you are not keeping the data for longer than necessary and that you can prove a lawful basis for having those details in the first place.
  • If you are not the entity that the user consented to processing their data, you must be legally permitted to process it and should make it clear in any emails why an email is sent from you rather than the entity you are subcontracted to. For example, "Dear Simon, Example Inc are acting on behalf of Acme Ltd to process any returns. Since you have recently returned an item, we hope that you can spare 2 minutes to tell us how the process went." In any case, you should use personal information in the message to add assurance that you have more than just an email address.


  • Avoid long subjects with mixed numerals and capital letters, as these can be picked up as spam by recipients’ email filters.
  • Avoid bland and imprecise subjects like "Feedback needed", since these are much less engaging and more likely to be ignored. Instead, something like "Feedback for you experience" means someone can easily just delete it immediately if they are not interested and are less likely to mark it as spam.
  • Try and avoid words and phrases that would commonly be used in Spam emails. Phrases that include urgency such as "complete these as soon as possible" or "action required" should be avoided.

Message Contents

  • Ensure any images used in the email have alt text.
  • Do not use link shorteners. Real links are much easier for a user to verify and are less likely to be considered SPAM.
  • For email tool survey invitations - Do not remove the [SURVEYLINK] tag. This will automatically be merged with the unique survey link for that respondent so they can be tracked correctly. If you need to add a custom variable to the link, or otherwise control how it's displayed in the email in detail, replace it with [SURVEYLINK_NL]
  • Check that any other URLs used in the email content are complete and load their targeted pages.
  • Try and avoid words and phrases that would commonly be used in Spam or Phishing emails. Phrases that contain too many superlatives like "amazing", "you won't believe" etc. are phrases that are likely to score highly on a SPAM trap.
  • Ensure your message is not too short. For example, if sending to your own staff where you might not need a large introduction, short messages like "Here is the link I mentioned" could trigger a SPAM trap.
  • Try and personalise the email with e.g. "Dear Simon". This makes the message less likely to be detected as a mass mailing and also helps the recipient know that you have their real contact information and haven't just stolen an email address, which reduces the chance of a recipient marking the email as SPAM.
  • You should always indicate to the recipient why they are receiving the survey link e.g. "Since you recently purchased an item from Acme, we would really appreciate it if you could spare 5 minutes to give us some feedback". This, again, reduces the chance of having your emails marked as SPAM.
  • SmartSurvey should not be your main contact list so you should provide any legally-required opt-out in each message to your contact lists. Although SmartSurvey includes an opt-out for our systems, a recipient will be happier to see e.g. "You can opt-out of any further emails from Acme by clicking this link".

Sending Frequency

  • For survey invitations, the system will send these in batches with a delay between each batch to avoid hitting any rate-limiting mechanisms. This is especially troublesome if you have many contacts that use the same email provider.
  • You should avoid sending too many survey invitations to the same people on the same day. Getting multiple similar emails from the same email address or email server will look suspicious to a SPAM trap.

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