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Understand your sender reputation
Understand your sender reputation

Your account's sender reputation is an important indicator of good email marketing practice.

Gareth Burroughes avatar
Written by Gareth Burroughes
Updated over a week ago

Sender reputation is calculated from the quality of data you upload and the engagement you get from your contacts for your campaigns. The better this data is, and the greater your campaigns perform, the higher your sender reputation will be.

Knowing your sender reputation lets you take steps to improve it, should you wish or need to.

Find your sender reputation

  1. Expand the User menu and select Settings.

  2. Go to General > Sender reputation.

Your sender reputation is displayed here, along with your reputation indicators.

The different reputation statuses are Bad, Neutral, Good and Very good, and this range is applied to all reputation indicators.

You may see another status sometimes: Evaluation. This means that we don't currently have the information needed for this reputation indicator. It gets updated once we do.

How we calculate sender reputation

There are a number of reputation indicators used to calculate your sender reputation, and these are based upon all of the campaigns you've ever sent. These are your open rates, click rates, complaint levels, bounce levels, and your Data Watchdog scores. We evaluate sender reputation scores every 14 days.

The key is that if you're doing everything well - using good quality data and sending engaging campaigns to those good quality contacts - you'll have a good sender reputation score.

Improve your sender reputation

As we've said, the best way to improve your reputation is to ensure you're doing everything well across the board. In short, try to make sure the data you're using is of as high a quality as possible, coming from a good and trustworthy source, and strive to make the campaigns you're sending as engaging as possible.

However, below we provide some more detailed guidance about improving your reputation indicators.

Open rate

The open rate is the percentage of recipients who actually opened your sent campaign. This indicates how engaged your list is with your campaigns and their content during a given period.

If you want to improve your open rates, here are some key points to pay attention to:

  • Reactivate your inactive subscribers and then clear out your remaining non-openers.

  • Create consistency and urgency in your campaigns.

  • Create targeted segments around subscribers' individual preferences and behaviour, and personalise content based on their usage history.

  • Cut out words that trigger spam filters.

  • Make your campaigns mobile responsive.

  • Resend unopened emails.

  • Send transactional email and marketing email on separate IPs.

  • Simplify your entire email messaging.

  • Experiment with sending times.

  • Send a Welcome campaign immediately after a contact subscribes to your emails, which immediately helps you to verify the email address.

  • Use direct, click-worthy subject lines that inspire curiosity.

Set expectations when collecting an email address

  • Ask permission to send to your contacts at the point of signup.

  • Include a link to your privacy policy and make sure it includes a clear outline of what emails you send, who they’re sent to, and how email addresses are shared (or not shared).

  • If you offer different types of email or send for multiple brands, make sure you give your recipients control over what they receive by providing a preference centre.

  • Send a Welcome email that provides information about the emails the subscriber has signed up to receive.

Click rate

The click rate is otherwise known as the unique user click-through rate (CTR) and it's a percentage of the recipients who clicked through on your email, taken against the total emails delivered.

Send content that is recognisable and expected

  1. Send emails that are consistent with what subscribers were told they'd receive at the point of signing up. Meet their expectations.

  2. Use segmentation to send subscribers content that speaks to them and their personal interests.

  3. Make sure the frequency of emails is consistent with what the subscriber is expecting.

  4. Make sure the branding is consistent and recognisable to the recipient.

  5. Use recognisable and consistent From and Reply to names and addresses, as well as recognisable and consistent subject lines to ensure that the subscriber recognises your mail.

  6. Test your content to ensure that it appears and comes across as you intend.

Pay close attention to inactive contacts

  1. Create an engagement strategy; make sure you're sending email to subscribers that want your emails

  2. Remove subscribers who are showing signs they don't want - or aren't interested in - what you're sending them

  3. Make your engagement strategy ongoing. Actively remove risky subscribers that could negatively affect your sending reputation.

  4. Implement a company-wide suppression list.


Email abuse complaints made against you have the potential to adversely affect your deliverability. Too many abuse complaints, and/or increased abuse complaints, can lead to your sends being blocked by an ISP or email receiver. These blocks cause delays and can sometimes grow into more serious issues, requiring intervention to put it right.

Here's some key advice to help you steer clear of complaints.

⚠️ Important notice

Dotdigital’s Terms of Service prohibit uploading or sending to purchased email addresses.

  1. Avoid using purchased lists
    Have you ever been tempted to grow your list by a million potential customers in no time? Have you been to forums where thousands of targeted leads are sold for a small fee?

    Purchased lists are ticking time bombs, just waiting to seriously harm your reputation as a sender. Riddled with dead emails and spam traps, they quickly inform mailbox providers that you break the rules by sending unsolicited emails.

    At best, your messages may end up in junk folders. At worst, you may be branded as a spammer.

    If you still purchase lists, stop now.

  2. Employ good practice

    • Add complaining subscribers to a suppression list as soon as you receive their complaint.

    • Use your brand name in the friendly from name (display name) field so it's easier for subscribers to recognise your email.

    • Ensure that you're sending relevant content to encourage engagement.

    • Set expectations at the point of signup about what emails a subscriber can expect to receive and when they should receive them. Meet those expectations with the subscriber.

    • Send consistent volumes by establishing a regular sending cadence and avoid large-send volume spikes that may trigger a corresponding spike in complaints.

  3. Avoid dirty tricks

    What may have been effective a decade ago no longer works today. Remember, being caught red-handed in any of these practices may cause permanent damage to your deliverability ratios:

    • Hashbusting: Inserting random characters in the subject line or content to fool spam filters, e.g. 'F.ree. p.r!z.e'.

    • Deceptive subject lines: Starting the subject line with 'Re:' or 'Fwd:' to suggest an ongoing communication with the sender.

    • Misleading claims: Using a subject line that state that the recipient has won a prize, while the content lists conditions that have to be met in order to claim it.

    • Image text: Concealing a text message in an image to fool spam filters.

Data Watchdog

When importing contacts in a file, it could be the case that the data is not as clean, reliable or as safe to send to as you have reason to believe. Our Data Watchdog provides a unique checkpoint which is constantly on the lookout for any such questionable or risky data.

Your contact imports either get cleared, flagged as 'at risk', or they're quarantined.

Therefore your Watchdog score is based upon your history of Data Watchdog results.

Learn more about the Data Watchdog.

Hard bounces

In general, a bounce is when an email can't be delivered to an email address. There are many different reasons why emails bounce. When it happens, a 'return to sender' message is sent from the recipient's mail server to explain why.

There are two types of bounces that you can receive - a soft bounce and a hard bounce.

A soft bounce means that the email address was valid and the email reached the recipient’s mail server. However, it bounced back because:

  • The recipient mailbox was full (the user is over their quota)

  • The recipient's server was down or experiencing issues

  • The message was too large for the recipient’s inbox

A hard bounce occurs when the message has been permanently rejected because:

  • The email address is invalid

  • The email address doesn’t exist

These hard bounced email addresses are added to your suppression list. Continuing to try to send to a known bad email address will harm your reputation with the receiver, so we prevent it.

You can think of soft bounces as a short-term issue; you don’t need to permanently take these email addresses off of your list. Hard bounces, on the other hand, are either invalid or non-existent email addresses that should be removed immediately (which we do automatically).

The difference between a bounce and an ISP complaint

When an email can't be delivered to an email address, it's called a bounce. An ISP complaint, on the other hand, means the message was delivered to the recipient, but they marked the message as spam. When an email is marked as spam or junk mail, an abuse report is created. The report is automatically sent to the recipient's ISP and a warning is sent to us. These are normally sent in what we call ARF, or abuse reporting format, and are automatically processed by our platform.

Normally these will mask the recipient identity of the complainant and will include a copy of the email which was sent. It also includes a brief message stating that their customers are complaining about your emails and that action must be taken to address the issue or our server will be blocked.

Soft bounces

There are many different types of soft bounces. The following categories will not apply to every bounce type out there. We take a simplified approach to bounce message interpretation based on industry best practices.

  • General bounce: This is treated as a soft bounce because we can't determine the exact reason for delivery failure. Typically, this bounce type is associated with a technical issue such as a connection timing out, but we'll also classify a bounce as 'general' if the response from the recipient server is open to more than one interpretation. It could be a non-standard error message, or too vague to be useful.

  • DNS failure: The recipient's email server is currently unable to deliver your email due to DNS issues on their end. This may or may not be a temporary problem. The error could be due to the mail server being down, or there was a typo when it was set up, or maybe the destination domain doesn't exist. All we know is that the DNS host is unreachable, therefore we treat this as a soft bounce to allow some time for the problem to be rectified.

  • Mailbox full: The email server can't deliver your email because the recipient's inbox is full. Most email applications have a set amount of storage an individual user can use for email. If this quota is exceeded the server won't let any more mail through, but it will also usually alert the mailbox owner so they can do something about it. So while it may be the case that your recipient hasn't put aside time to make some space, it could also be a sign of an abandoned mailbox. For example, this could happen when someone sets up a free webmail account just for shopping-related emails, then stops signing in when they start saving for a house. We treat these as a soft bounce in case it's temporary, but if the issue continues we'll convert it to a hard bounce for you.

  • Message too large: The size of your email - including all headers, text and images - is larger than the maximum size that the recipient's mailbox allows. The bounce message returned doesn't include information on what the size limit is, but the Dotdigital deliverability team will advise you not to send messages larger than 500KB.

  • Transient bounce: The recipient mail server can't deliver your email, but will keep trying for a limited period of time. We treat this as a soft bounce, as when the recipient mail server retries the message could be delivered.

  • Challenge/response: The recipient has installed software as an anti-spam measure, and it only accepts email from previously authorised senders. If the software doesn't know the sender, a challenge email is returned, requiring a specific action before the original email will be sent to the recipient. Since the requested response could be anything, we treat these as a soft bounce.

  • Bounce - but no email address returned: The recipient mail server bounced your email, but didn't indicate which address it was bouncing on behalf of. We have determined the recipient based on the content of the bounce.

If you need to know more about specific bounces for your campaigns, first check out your campaign reports for more information. If this isn't sufficient and you still have concerns about the delivery of your campaign and the bounces you're receiving, please contact the deliverability team on

Mail blocks

  • Mail block - relay denied: Your email has bounced due to a temporary error, which could be on the sending or receiving side. 'Relay' simply refers to the transmission of your email from our server to the receiving server, which has most likely been denied due to user error. This type of bounce usually occurs when the sender's message isn't authenticated, but it can also be due to a misconfigured server on the recipient side. Technically speaking this is a hard bounce, but we treat it as a soft bounce because it's often a result of user error, which can be resolved.

  • Mail block - general: The recipient's email server is blocking inbound mail from our server, which may be due to block listing. A mail block is recorded when the receiving server blocks an email completely; rejecting the message without any attempt to deliver it to the inbox. The most likely reasons for this block are:

    • Your reply-to address is block listed

    • One of our sending IPs is temporarily blocked

    • One of our sending domains is temporarily block-listed

    • The receiving server only accepts allow listed senders

  • Mail block - spam detected: The recipient's email server has blocked your email on the basis that the content resembles spam. This mail block is often triggered by something detected in your email content, but can also be because your reply-to address or brand name has a poor reputation. We treat this as a soft bounce due to the fact that some mail servers and email providers respond with false or incorrect error codes.

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