Email suspension upon increase in the bounce rate and spam rate

Modified on Fri, 02 Feb 2024 at 05:34 AM

An email bounce occurs when an email cannot be delivered to an email server. In other words, an email is considered to have been bounced when the recipient’s email server rejects the email message and the mail doesn’t arrive in its intended mailbox. It means that for some reason, the email hasn’t been or can’t be delivered, and consequently the email server redirects it back to the sender.

In NotifyVisitors, the bounce rate is a measurement of how often your emails bounce. The bounce rate has a significant impact on your sender reputation. A high bounce rate combined with a greater number of emails marked as spam eventually undermines your sender reputation. In order to safeguard your sender reputation and improve your deliverability scores with ESPs, it is imperative to track the bounce rate of your email campaigns. NotifyVisitors tracks each user’s complaint rate, bounce rate and takes adequate measures to stop spammers.

Types of email bounce

Soft bounce

A soft bounce is an email that couldn’t be delivered to the recipient’s email server because of resolvable temporary reasons that are oftentimes outside your own control. The reasons for soft bounces are as follows:

  • The email server is down.
  • The recipient’s mailbox is full.
  • The email’s size is quite large (this happens in rare cases).

There is not much that can be done to successfully deliver an email in case the email server is down or your recipient’s mailbox is full. Nevertheless, you have direct control over the size and content of your email. You can truncate the email’s textual content, crop images or reduce their overall size and image quality, curtail or completely remove dynamic media in order to create a lighter and a more focused email.

In case of a soft bounce, the email service provider resends the email. However, usually any repeated, unchecked and unresolved soft bounces are eventually converted into a hard bounce by your email service provider. Simply put, while a soft bounce is an issue that needs to be solved, it isn’t dangerous to your sender reputation until it becomes a hard bounce.

Hard bounce

A hard bounce occurs when an email is sent back due to permanent and unresolvable reasons. The causes of a hard bounce are varied, but most of the time the recipient’s email address is invalid or no longer in use because of the following reasons:

  • The email address is mistyped.
  • The server is not accepting emails.
  • The domain does not exist (i.e. the portion of the email after the ‘@’ symbol).

The most important distinguishing factor between soft and hard email bounces is that a hard bounce can damage your deliverability rates and your sender reputation, putting you at direct risk of being treated as a fraudulent email sender. The status of being a fraudulent email sender will impair your email deliverability and this status should be avoided at all costs.

How NotifyVisitors evaluates deliverability

When we advise customers on deliverability, we look at the following ranges of the key email metrics as shown in the screenshot provided below.

The acceptable email bounce rate

The number of bounced emails is linked directly to the quality of your contacts list. A low bounce rate viz. up to 1% indicates an engaged, well-maintained contacts list, populated with real and active subscribers who are genuinely interested in receiving your email campaigns containing product related offers, promotions and updates.

The industry standard for an acceptable bounce rate is less than 3%. In case the Bounce Rate of your email campaigns begins to surpass that figure, you should track and monitor your campaigns in order to make sure that the Bounce Rate doesn’t continue to climb. If your bounce rates get up over 5% then you might have a serious problem with your list that should be taken care of.

NotifyVisitors follows the industry standard and so the percentage of bounces must be less than 5%. When it is between 3% and 5%, your account is put on probation and if the bounce percentage equals 5% or exceeds 5%, then your account will get suspended.

Then, we can send you email alerts when the number of bounce emails reaches or exceeds the values specified by you. We help you identify the peaks of bounce emails and understand which email campaigns generated the highest bounce rate.

Important Note

NotifyVisitors will suspend the user’s account if the bounce rate is equal or exceeds 5% of the volume of sent messages during a single campaign. You will be proactively informed when the quantity of your bounce messages is reaching the allowed threshold. We will provide a suspension time from the backend after discussion with the client.

The acceptable email spam rate


Spam is any type of undesirable, irrelevant, unsolicited digital communication that is sent out in bulk to a large number of Internet users, for the purpose of illegal advertising as well as other activities such as phishing and spreading malware. Spam is often sent via email. However, it can also be distributed via SMS, phone calls, or social media. It is the most inexpensive way of commercial marketing. Spam emails are also called junk emails. Although annoying, spam messages often come in the form of harmless promotional emails, but sometimes spam can be a fraudulent or malicious scam. Spamming is the act of sending spam messages and the person who sends such messages is called a spammer.

Spam rate

The spam rate is the percentage of emails that are considered as spam. This percentage can differ depending on the service or provider you employ. The spam complaint rate is the percentage of email messages that are reported as spam by the recipients. This rate is measured by dividing the number of spam complaints by the number of total emails sent by your organization.

The acceptable industry standard for the spam complaint rate is anything less than 0.1%. In other words, 1 complaint for every 1,000 messages sent, is the acceptable industry standard. Anything above this specific level is considered high. This is the industry standard set by major inbox providers such as Gmail.

NotifyVisitors follows the industry standard and so the percentage of spam emails must be less than 0.1%. In case the spam rate for your email campaigns equals 0.1% then you will receive a warning email from our end, informing you regarding the same. However, in case the spam rate for your email campaigns equals or exceeds 0.3% then your account will get suspended and you will receive a warning email informing you about your account’s suspension. The spam limits will also be mentioned within these warning emails.


In case your account gets suspended, then in order to reactivate it you will have to contact the NotifyVisitors Support Team.

Click here in case you want to learn more about dealing with email campaigns falling into spam.

Primary reasons for hard bounces and how they affect deliverability

The common reasons for Hard Bounces are as follows:

  • You might use free email services like Gmail, Yahoo, AOL etc. as an email sender. In order to minimize fraudulent emails, several email service providers have changed their DMARC policies. As per the latest policy, your emails will not pass the authentication and will get bounced. In case you carry out an ecommerce business, you should use an email with a private business domain such as
  • Your mailing list might not be up to date. In case your mailing list was prepared several years ago, and you decided to use it in the present time, don’t be astonished by a high bounce rate. This is because your subscribers/contacts might have changed their emails, forgotten about your organization, or might no longer be interested in your content. So, you should delete those users from the mailing list who have been inactive for months.
  • You rented or bought a mailing list. When you construct an email list organically, you acquire subscribers who are genuinely interested in your brand. On the other hand, when you purchase or rent a mailing list, you don’t. These kinds of mailing lists often include inactive, old  and spam trap email addresses that cause high bounce rates and lead to blacklisting. So, as a best practice try not to ever purchase or rent a mailing list.
  • You suffer from typing errors. In case your subscriber list is brand new but the bounce rate is high, then the problem might be in the way it was set up. People tend to mistype their emails. So, you can skim your contacts and check for mistypes such as, @yahoo.con, etc. You could also use email verification to ensure proper email grammar and validation. 
  • It is important to allow for an easy, hassle-free unsubscribe somewhere within your emails. It is better to lose disinterested contacts rather than make them feel irritated enough to mark your emails as spam.


We do not recommend usage of purchased or rented lists.

How to avoid a high bounce rate

  • In case you notice an abnormally high bounce rate, then you might have to conduct an old-fashioned email list cleaning. Fortunately, this is a quite simple process, and should be done from time to time to maintain a proper mailing list.
  • Begin by segregating unengaged contacts from your mailing list. These are essentially those contacts that haven’t interacted or engaged with your campaigns in quite some time. What you can do from your end is that you can send a re-engagement or a reactivation campaign. Such campaigns will enable you to discern which contacts should be removed completely. If they don’t respond or engage with the emails, then for sure it’s time to remove them.
  • Don’t forward your campaigns to those contacts who aren’t interested. They don’t wish to receive them, and sending them mails anyway will not do any good to your business or to your sender reputation.
  • Additionally, you can even choose to use an email list cleaner to distill/cleanse your mailing list to include only those email addresses which are active. All you need to do is upload your mailing list to a list cleaning service, which will in turn validate the email addresses and automatically remove any that can’t receive an email.

Important Note

All inactive email addresses might not get filtered out via mailing list cleaning services, nevertheless it’s a good preliminary step. You may have to segregate non-functional email addresses once your mailing list has been scrubbed.

Bounce email warnings and alerts in NotifyVisitors

Email Bounce alerts will be sent when the number of bounce emails reach or exceed the control value within a predefined interval. 

In case the Bounce Rate is within the range of 3% to 5%, then a warning mail will be sent to the customer that their account has been put on probation and in case the Bounce Rate equals or exceeds 5%, then a warning mail will be sent to the customer stating that their account has been suspended. Kindly note that in order to reactivate your account you will have to contact the NotifyVisitors Support Team.

Within the warning emails, we inform and mention about the hard bounces, soft bounces, unsubscriptions as well as the spam limits. For instance, in case the number of unsubscriptions exceed the unsubscription limit, then within the dispatched email warning, it will be highlighted that the unsubscription limit has been exceeded.

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