Avoid the Spam and Bounce Traps

When using a newsletter to contact a large database of subscribers, it's perfectly normal to want to reach the "Holy Grail" of 100% email deliverability, with zero bounces or spam reports.  But how feasible is that? Is it even possible? Let's discuss and find out!

In this article, we will look at the following (click to jump to section):


Spam complaints and what is a "normal" rate? 

Spam complaints are reports made by email recipients against emails they don't want in their inbox. Most mailbox providers - usually Internet Service Providers (ISPs) - include a prominent "This is Spam" button in the inbox to allow people to report unwanted emails. People click the spam (or junk) buttons for various reasons, such as:

  • they're confused about who you are, or why you're emailing them
  • they can't find the unsubscribe link  
  • some people incorrectly use the Spam button instead
  • some people accidentally hit the spam button by mistake

Even legitimate senders get spam complaints so it's important to understand how spam complaints work and how you can do your best to avoid them.  A few spam complaints are inevitable but excessive  complaints can cause big headaches for you and for us. An email that receives a large number of complaints, could result in your next email being blocked by ISPs, so that even people who do want to hear from you may not get the email.  It can also lead to our server sending IP addresses being blacklisted, which means we have to do a lot of work to untangle that.  Ultimately, severe or considerable damage costs associated to a major spam email could be incurred by you.

How is spam reported / recorded?

Spam complaints are recorded in your sent email report, when we receive spam notification feedback from ISPs. The spam percentage displayed in reports is calculated based on the number of complaints made in comparison to the total number of emails sent. Every complaint received is recorded in our system, and we regularly calculate the percentage of complaints generated by each email.

Recipients who report your email as spam are immediately unsubscribed from your list, meaning you will no longer be able to send emails to that individual. Their email address is also added to your suppression list. This is to protect you, us and the complainant.

What is a normal spam rate and what happens if yours is higher than normal?

Industry standard for spam complaints is less than 0.02%. That's about one complaint for every 5,000 recipients.

If you send an email that receives more than a 0.2% complaint rate, we will notify you with a warning email that includes advice to help you address the situation. We understand that even legitimate senders get complaints so, provided you're doing the right thing, do not be alarmed if you get a warning email from us.

If complaints for a single email exceed industry thresholds — anything above 0.5% — your account could be suspended.


What is a Bounce and what is a "normal" rate?

When an email message cannot be delivered to an email address, it's called a bounce. There are lots of different reasons why emails bounce so, when it happens, a "return to sender" message (or, SMTP reply) is sent from the recipient's mail server to explain why. We process bounce replies and include them in the "Bounce Summary" section of your reports.

To view the bounce summary for a sent campaign:

  • Click Campaigns, then click on the relevant campaign under "Sent Campaign Reports".
  • On the report page, click Bounce Summary in the right sidebar.
  • On the bounce summary report page you can search bounces by recipient name or email address:

The bounce summary report lists any email addresses that bounced, and the reason why. The error message returned is used to classify each email address as a soft or hard bounce, meaning a temporary or permanent delivery failure.

Soft bounce

A soft bounce is a temporary delivery failure: your campaign was receiving at the recipient's mail server, meaning the email address was recognized, but the message bounced back undelivered instead of reaching the recipient's inbox. Soft bounces can occur when

  • the recipient's mailbox is full;
  • the receiving server is down or swamped with messages;
  • the message size is too large;
  • the recipient's settings do not allow for email from the sender;
  • suspicious or spammy content has been detected, and many more reasons.

It does not necessarily mean the email address is invalid or no longer active, so while we have stopped trying to deliver your last campaign, we will try to send the next one to these addresses.

Hard bounce

A hard bounce is a permanent delivery failure. When you get a hard bounce it means the recipient's email address is invalid or no longer in use. Typically the domain name (the bit after the @) no longer exists or it no longer has registered mail servers. But it could also be invalid due to typos, for example gnail instead of gmail.

Email addresses that hard bounce are automatically removed from your subscriber list so you don't pay to send to them again. We also add them to your suppression list which prevents the addresses from being accidentally re-imported.

What is a normal bounce rate?

One of the most important metrics to monitor after you've sent a campaign is the "bounce rate", which is the number of bounced emails divided by the total number of recipients the campaign was sent to. A bounce rate percentage is calculated for every campaign you send and displayed on the snapshot page of your campaign report.

Bounce rates are directly related to the quality of your subscriber list. Low bounce rates are a sign of a healthy, permission-based list, but a high bounce rate indicate that there may be problems with the way your list was grown, or how it is being managed.

 A healthy list bounce rate is between 2-5%. If you are regularly see higher bounce rates, get in touch

We can help you investigate the cause of high bounce rates and work out how to fix the problem, so please do contact us. If your bounce rates are regularly exceeding the industry standard of 2%, it may result in your account being suspended in which case we'll have to get in touch with you anyway.


Newsletter Sending Best Practice and Tips 

You may find out from subscribers, or by sending test emails, that your emails are being sent to the junk or spam folder, or they are bouncing instead of getting to the user's inbox. Here's some advice on what to do, but feel free to reach out to us so that we can assist you further.

Avoid Spammy Content

The number one way to get sent straight to spam is to use spammy content - so avoid at all costs! Spam filters look at an email as a whole, and score the content according to pre-set algorithms with thresholds set for certain criteria. If a threshold is exceeded, the email gets marked as spam and will not be correctly delivered.  Some ISPs work in a "hive" mentality - so if an email is marked as spam for a number of the same customers, the ISP will automatically blacklist it for all of their customers.

Things that can be caught by spam filters can include:

  • An entire email composed of capital letters
  • Frequent, random capitalization
  • Excessive punctuation, especially "$" and "!"
  • Strange spacing or excessive amounts of blank space
  • Poor spelling
  • Frequent variations in text color and size
  • Scam-like subject lines

Emails that contain unbelievable claims about earning money fast, free products/services, adult content, gambling, prizes and pharmaceuticals are also high risk for being marked as spam (and are all prohibited by our terms of use).

Before sending an email, you can also opt to run our design and spam test to test your content against spam filters from MessageLabs, Spam Assassin, Outlook, Gmail and Yahoo. There may be an additional fee for this on your account.

Avoid spam filters

One way to avoid spam filters is to ask your subscribers to add your email address or domain to their safe sender lists (Outlook 2003–2016), address books (Apple Mail, Mozilla Thunderbird) or contacts (Gmail, Yahoo, Outlook.com, AOL, iOS). Usually the best time to do this is in your introductory email, or on your subscription confirmation page, or in the footer of the email you are sending.

Authenticated domain / email

Depending on how an inbound email server is configured, it will use various methods to determine whether an email comes from:

  • the server it claims it is from
  • the email address it claims it is from
  • a server that has been authorized to send on behalf of that email address.

To address this, we will usually insist that you send from an authenticated domain, add relevent DKIM and SPF records to the domain DNS.  We can either do this for you, or you could do it yourself assuming you have the necessary access and skill to do so.

Adhere to CANSPAM and other standards

Anti-spam legislation of several countries requires organizations sending marketing emails to include a valid, physical postal address. There are different anti-spam laws for different countries but the inclusion of an address is a good idea.

A "physical address" means the mailing address for your business; a phone number is not required. It can be your current street address or a registered post office box (P.O. Box address). The most common position for placement is the footer of your template (or the bottom of your campaign content) because that's where people will scroll down to look for it.

For home-based businesses, it's understandable if you don't want to share your home address with subscribers. However, you must still supply an address; it just needs to be somewhere you can receive postal mail - so if you don't already have one, get a P.O. Box address

Unsubscribe Link

All campaigns must have an unsubscribe link prominently displayed. By default we always include these, so you should not need to be concerned.


Some people are happy to receive your email news every day, others might only want one per month. To avoid annoying your customers, why not give them the option of when to receive your emails?  You could set up several lists, e.g. a daily, monthly or quarterly list.  You can also give subscribers subject matter options, for example if you have different services / products, it would be possible to add these as options in the sign up preferences section.  For more information on this and other ideas, get in touch via the link below.



Further help from Purple Dog

We would be happy to answer any additional questions you may have. Please do get in touch.


Back to Top

  • spam, email filter, bounce rate, newsletter
  • 2988 Users Found This Useful
Was this answer helpful?

Related Articles

Send your first campaign

Find out how to use the create send software to send your first email newsletterTo get started,...

Resend a campaign

Any previously sent campaign can be duplicated with a single click, making it easy to send...

Import subscribers

Provided you have obtained the correct permission from your recipients, you can import...

IMPORTANT: Sending permission policy

We employ a very strict anti-spam policy that is supported by a strong permission policy....

About Open Rates

Find out what an open rate is, how it is measured and calculated, and whether your open rate is...