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Bounce rate and Spam complaints

Updated over 3 weeks ago

You may already be familiar with the concept of deliverability rate. Bounce rates reflect the opposite: while deliverability rates compares the number of the emails that reached an inbox with the number of emails sent, bounce rates compare the number of sent emails and the ones that did not reach a recipient. By definition, then, an email's bounce rate reflects the number of emails rejected by the receiving server.

In the reports from your newsletter send outs you can see how many email messages that have bounced. A bounced email is an email that for some reason could not be delivered to the recipient.


Bounces can be divided into different categories:

Hard

Hard bounces are the ones to look out for!
A hard bounce is typically due to the e-mail address not being valid. The e-mail address might be misspelled or non-existing or the email account might also have been closed.
If a hard bounce happens three (3) times for the same recipient, APSIS Pro will automatically unsubscribe and place the recipient in the Opt-Out-All.

Hard bounce reasons

Category

Reason

Description

Hard

General hard bounce

Failed to deliver the message due to unspecified permanent error.

Hard

Invalid recipient

The email address is either misspelled, or does not exist.

Hard

Bad domain

The domain name is either misspelled, or does not exist.

Hard

Address error

The email address might contain invalid characters.

Hard

Closed account

The recipient's mailbox has been closed.


Soft

A soft bounce means that the e-mail address does exist, though the recipient's inbox might be full and can therefore not receive any e-mails.

Soft bounce reasons

Category

Reason

Description

Soft

Mailbox is full

Recipient's mailbox is full or has exceeded storage allocation.

Soft

Server is currently too
busy

Unable to deliver the message to the recipient due to temporary error on
receiving side.

Soft

Account is inactive

The recipient's mailbox is inactive.

Soft

Data format error

Format error somewhere in the data.

Soft

General error

Failed to deliver the message due to unspecified reasons.

Soft

Network error

Unable to deliver the message due to a network related error.

Soft

Other receiver error

Failed to deliver the message due to unspecified reasons on receiving
side.

Technical bounces

This type of bounce might be due to a temporary problem at the recipients e-mail server. The server might not have been available at the time of the sending, it might be temporarily down, overloaded etc.

Technical bounce reasons

Category

Reason

Description

Technical

Server is currently too
busy

Unable to deliver the message to the recipient due to temporary error on
receiving side.

Technical

Network error

Unable to deliver the message due to a network related error.

Technical

Other receiver error

Failed to deliver the message due to unspecified reasons on receiving
side.


Other

Other bounces mean that the bounce message cannot be placed in a specific category. Because there is no general standard for bounce errors, there are thousands of different bounce strings in different languages. We continuously work on refining and classifying bounce messages, but it is not possible to do so for all of them.

Other bounce reasons

Category

Reason

Description

Other

Other

Unknown reasons

Other

Unknown

Unknown reasons


High Bounce rate

Monitoring bounce rates and spam complaints is essential when sending emails to APSIS Pro recipients. After your email is sent, you can review bounce details by checking the Report from your email send out periodically over the next 2–3 days.

Of course, preventing bounces is just as important as taking measures after noticing a high bounce rate. A bounce rate of less than 5% is considered normal, and as long as you are actively and periodically taking steps to prevent bounces, there is no need to worry.

However, if your bounce rates are...

5% or Higher

10% or Higher

A bounce rate of 5% and up is a concern. We recommend you to review the Reports of the last few Emails you have sent.

Then, look at the tasks described below on how to prevent bounces.

If you notice a lot of hard or technical bounces, we suggest you contact

A bounce rate of 10% and up is considered a bad sending. There could be something wrong with the email addresses you have sent to, or a problem with your Email Authentication setup.

We recommend that you contact Customer Service for us to help you as soon as possible.

How to Prevent Bounces

Here is what you can do to help prevent bounces.

  • Clean up inactive recipients
    Identify inactive profiles and unsubscribe or delete them.

  • Re-engage your inactive recipients

    Design a re-activation campaign to target your inactive recipients. If they do not respond positively, you can confidently exclude or remove them from your APSIS Pro account.

  • Ask your recipients to whitelist you

    You may include a message in your Welcome emails, especially to address the cases in which the Email may wrongfully land in the spam folder.

  • Keep track of bounces and spam complaints

    Do not send to recipients who bounced, unsubscribed or reported your emails as spam.

  • Import new recipients sensibly

    Make sure that all addresses are real and provided with consent.


Spam Complaints

Spam or spamming refers to the action of sending bulk email messages for marketing or advertising purposes without the recipients' request or consent. Spam complaints in your Reports reflects only the number of recipients who reported an Email as spam.

Thus, this number does not reflect the full number of emails that landed in a spam or junk folder. The reason that emails sometimes arrive to a spam or junk folder is usually previous spam complaints, technical reasons and the reputation of the sender. Your sender reputation can be greatly affected by consistently sending to spam traps.

Spam traps are email addresses created to identify spam. Since they do not belong to a real individual, sending to a spam trap email address means that you obtained the address without consent.

Spam traps can be tricky to deal with, but sending to them greatly increases your chances of getting emails stuck in a spam or junk folder. There are three types of spam traps:

  • Pure spam traps - created artificially to lure spammers and have never been associated to a real individual.

  • Recycled email addresses - emails that once belonged to an individual but they have been abandoned for so long that the email provider has repurposed it as a spam trap. If you happen to send to a recycled spam trap, it shows that you have failed to keep your recipients up to date and have not cleaned up inactive recipients.

  • Invalid email addresses, which may be invalid either due to a typo or that an individual purposely provided a fake email address.

How to prevent Spam complaints

As long as you maintain a steady sending schedule, steady frequency and a good data hygiene - spam complaints should stay low.

However, you might want to ensure:

  • your Email Authentication is all set.

  • all Users in your account are aligned with your deliverability efforts.

With authentication in place and knowledge about how to keep deliverability high, you minimise risk for spam complaints.

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