Why Do I See Such a High Bounce Rate for Emails from Apollo?

Article author
Eric Zrinsky


There are several factors to consider when you notice that lots of the emails you send from Apollo bounce. Keep in mind, an industry-accepted average of about 10% bounce rate is considered normal. If your bounce rate is substantially higher than this, review the sections below for more information about the 2 types of email bounces and their potential causes.

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Soft Vs Hard Bounce

There are 2 types of email bounces:

  1. Hard Bounce—A permanent issue prevents your email from arriving in the intended inbox. Reasons include:
    • The email address is invalid or non-existent
    • The recipient's email server has blocked the delivery of your email
    • Your domain reputation is so low that your email is SPAM blocked. This means that it won't even reach the SPAM folder
  2. Soft Bounce—A temporary issue prevents your email from arriving in the intended inbox. Reasons include:
    • The recipient's email server is busy
    • The recipient's email storage is full
    • The recipient is not accepting emails for a temporary period
What Counts as a Bounce?

Please note, if your email lands in the recipient's SPAM folder, the recipient can still view the email if they wish to. Therefore, this does not count as a bounce.

When an email hard bounces it can damage your email domain reputation. If you consistently notice a high bounce rate (more than 10%) across all your Apollo Sequences, there could be several potential causes.

Refer to the section below for more information about each cause and the steps you can take to overcome each one.

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Potential Reasons For a High Bounce Rate

Third-Party Verification Services

Apollo has a robust algorithm for detecting valid email addresses. Often, this algorithm is more powerful than other third-party services like NeverBounce or ZeroBounce. Third-party verification tools may reject many valid emails as "catch-all" or "unknown." If you are using one of these tools, consider using Apollo as your verification tool.

Apollo Verification

Tell Me More!

For more information about email verification tools, refer to the "Email Verification: A Brief Introduction" article. If you want to learn more about the Apollo verification process, hop into the "Email Verification: The Apollo Process" article.

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Sending To Guessed Emails

Apollo gives you the option to associate guessed emails with a contact when you enrich their email address. If you or another user in your account has chosen to use this free enrichment service, contacts that include guessed emails have a higher chance of bouncing than the industry standard—typically around a 30%-40% bounce rate.

Guessed Email

If your emails are bouncing frequently in sequences that include guessed emails, consider using only verified email addresses.

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SPAM Blocked Emails

Apollo offers comprehensive reporting about all of the emails you send through the platform. This includes reporting specifically related to emails that bounce as a result of SPAM blocking.

Spam Blocked Email

To access reporting for Spam Blocked emails, launch Apollo and click Engage.


Click Emails.


Scroll to the right in the email bar and click Spam Blocked

Spam Blocked

Emails with the Spam Blocked tag have been blocked for several reasons that can include:

  • Domain reputation
  • Excessive send frequency
  • Email content & formatting like links, images, and lengthy paragraphs
Escape those Dreaded SPAM Filters

For additional information about how to avoid having your email SPAM blocked, refer to the "Avoid SPAM Filters" article.

If you notice that a large number of emails sent around the same time have been SPAM blocked, your email may include one of the reasons listed above. Edit your email template keeping email content and formatting best practices in mind. Then, wait a few hours before trying again.

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Email Addresses Provided By Other Tools

As an all-in-one lead generation and engagement tool, Apollo allows you to send emails to existing contacts from your CRM (like Salesforce or HubSpot) or CSV uploads. Apollo cannot guarantee the accuracy of email addresses provided by other third-party tools or sources.

Determine Whether Apollo Provided an Email for a Contact

If you want to check a specific contact to see if Apollo provided their email address, search for that contact or browse directly to their profile from a sent email.

Within that profile, scroll through the "Activities" on the right-hand side until you see a message that says:

Apollo's automatic email fulfillment found a verified email
[email@domain.com] for [Contact Name].


View the Data Enrichment Request Log

If Apollo enriched a contact with a verified email address and charged you a credit, you can view a log of that activity on the "Data Request History" page.

To access the "Data Request History" log, launch Apollo and click Settings.


Click Data Request History.

Data Request History

All data enrichment requests are available on this page. You can see the number of contact emails requested versus the number of credits charged for verified emails in each request.

Requested Vs. Charged

Click a specific request to view the contact information you requested.

Curious about Credits?

For more information about how data requests work in Apollo, refer to the "How Do Data Requests Work?" article. If you want to learn more about Apollo credits in general, refer to the "What Are Credits?" article.

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Natural Email Quality Decay

Email addresses are living entities. People may use them for some time and then may abandon them for any number of reasons, such as moving to a different job with a new email address. With this in mind, if Apollo provided you with a verified email address more than 6 months ago, we do not provide the same level of bounce rate guarantee. Contacts with verified email addresses older than 6 months may need additional enrichment.

Refer to the video below if you need help requesting an email address for a contact.


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