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Why Emails Bounce and What Actions to Take

Explains reasons for email bounces in campaigns and strategies to resolve issues, including handling different bounces.

Olivia Robinson avatar
Written by Olivia Robinson
Updated over 6 months ago

Understand Why Emails Bounce and How to Address It

With zkipster's invitations reporting sometimes emails can fall into two categories: soft and hard bounces.

Watch our tutorial video for a quick overview:

Soft bounces won’t need any immediate action, but may turn to a hard bounce if the email doesn’t get through. Keep an eye on these to ensure it gets delivered.

When an email hard bounces a triangle icon pops up next to the email and indicates either a code or a message for why the email bounces. Filter by your bounced emails, and hover over the Warning Triangle to see the reason behind the bounce.

If you have an error code with a specific number refer to this document from Sendgrid our third party email service.

Here are the 6 potential buckets that bounces can fall under, and what actions to take to try and overcome them.


1. Email address doesn’t exist/ Recipient Not Found

If the bounce is marked as “non-existent email address,” or "Recipient not Found" the email address could have a typo or the person with the address may have left the organization. Or, they may have given a false email address.

If a typo is found click on the guest within the invitations report, update their email and save, and it will direct back to the invitations report page. From there quickly check the box next to the guest's name and resend the invite.

In this case, it’s important to review the contacts in this category and see if there are any obvious typos in the email address. If not, try to reach the contacts by other means to confirm the address.

2. Email Undeliverable

If bounced emails are in the “Undeliverable” category, that means that the receiving email client is temporarily unavailable, was overloaded, or couldn’t be found.

A server that can’t be found could have crashed or be under maintenance, so this may just mean waiting to send the email to the address again.

However, if this email address repeatedly bounces on multiple emails, it may mean the server is gone for good.

3. Dropped

A dropped email means that the email address has had a previous bouncing history and therefore won’t be attempted to send.

If you have an email address with a 'dropped' status on your email deliverability report, please double check the address for any typos and confirm that the address is still active. In most cases, email addresses are dropped when they are invalid or inactive.

This is because sending emails to email addresses that do not exist, are inactive or cannot receive emails can affect the sender reputation. You can read more about sender reputation and how it can affect the deliverability of your emails here.

4. Guest’s Mailbox full

If your contact has so many emails in their inbox that they can’t receive more, your emails will bounce back until there’s space for them.

Sometimes, this can mean that the contact is no longer using that email address.

As with a non-existent email address, you may want to follow up with the contact by phone or mail to check whether the address is valid.

5. Blocked Email

If the email addresses are placed within the “Blocked” category, the receiving server has blocked the incoming email.

This is often the case among government institutions or schools, where servers can be stricter when it comes to receiving emails.

White labeling your domain and verifying your emails should help prevent this, but unfortunately we don’t have control over other people’s servers high security settings.

6. Other

Bounces that don’t give the server a reason for bouncing are put in this category, so it can mean that the email bounced for one of the reasons above or something else.

It’s important to keep an eye on these contacts, too, to see if the bounces keep recurring.

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