{"id":531,"date":"2023-07-04T11:22:57","date_gmt":"2023-07-04T08:22:57","guid":{"rendered":"https:\/\/snov.io\/knowledgebase\/?p=531"},"modified":"2025-03-31T15:29:59","modified_gmt":"2025-03-31T12:29:59","slug":"what-are-hard-and-soft-email-bounces","status":"publish","type":"post","link":"https:\/\/snov.io\/knowledgebase\/what-are-hard-and-soft-email-bounces\/","title":{"rendered":"How to fix and prevent bounced emails"},"content":{"rendered":"<p>This article explains hard and soft bounces, common delivery errors in <a href=\"https:\/\/snov.io\/cold-email\" target=\"_blank\" rel=\"noopener\">cold email automation<\/a>, why they occur, and how to fix them.<\/p>\n<p><span style=\"font-weight: 400;\">Bounces are email delivery errors that occur when emails fail to reach their intended recipients and are returned to your inbox.<\/span><\/p>\n<p><a href=\"#email-bounce-types\">Email bounce types --&gt;<\/a><\/p>\n<p><a href=\"#prevent-bounced-emails\">Prevent bounced emails --&gt;<\/a><\/p>\n<p><strong>Before we start, here are brief steps on how to identify bounces:\u00a0<\/strong><\/p>\n<p><b>a)<\/b><span style=\"font-weight: 400;\"> Send a test email from your primary email address (which sends campaigns) with your usual email content to your other email address.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">If you receive a bounce-back message in your inbox, open the delivery error report and review the information.<\/span><\/p>\n<p><b>b)<\/b><span style=\"font-weight: 400;\"> Check your inbox for undeliverable emails. These emails typically have subject lines such as <strong>\"Mail Delivery Subsystem\"<\/strong> or <strong>\"Your message couldn't be delivered.\"<\/strong> <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Examine the bounce reports for any recurring patterns or errors.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Bounce reports from email providers help determine the specific reason why the email could not be delivered.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Moving forward, we will outline the most common bounce examples to help you fix and avoid them in the first place.<\/span><\/p>\n<h2 id=\"email-bounce-types\"><b>Bounce types<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">There are two main categories of delivery errors: <\/span><b>hard bounces<\/b><span style=\"font-weight: 400;\"> and <\/span><b>soft bounces<\/b><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Based on what type of bounces you get more often, you can take the necessary actions to fix them and decide whether to continue sending your campaign bounced emails.<\/span><\/p>\n<h3><strong>Hard bounces<\/strong><\/h3>\n<p>A hard bounce is a permanent delivery error.<span style=\"font-weight: 400;\"> Any future attempts to send emails to that email address will most likely fail again.\u00a0<\/span><\/p>\n<p><b>1) Address not found<\/b><\/p>\n<p><span style=\"font-weight: 400;\">This delivery happens when the recipient\u2019s email address is invalid or the email account was deactivated.\u00a0<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-block-image shadow aligncenter wp-image-26498 \" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/address.not_.found_.png\" alt=\"\" width=\"800\" height=\"240\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/address.not_.found_.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/address.not_.found_-300x90.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/address.not_.found_-768x230.png 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\">\n<p><b>How to fix:<\/b><span style=\"font-weight: 400;\"> The email address couldn\u2019t be found because of a typo or the email address does not exist.\u00a0<\/span><\/p>\n<p><a href=\"https:\/\/app.snov.io\/bulk-email-verification\" target=\"_blank\" rel=\"noopener\">\u0421lean your recipients list<\/a> <span style=\"font-weight: 400;\">to clean it from invalid or outdated emails.<\/span><\/p>\n<\/div>\n<\/div>\n<p><b>2) Message blocked<\/b><\/p>\n<p><span style=\"font-weight: 400;\">This bounce occurs when the recipient\u2019s email server rejects incoming emails.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-block-image shadow aligncenter wp-image-26499 \" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.blocked.png\" alt=\"\" width=\"794\" height=\"238\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.blocked.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.blocked-300x90.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.blocked-768x230.png 768w\" sizes=\"(max-width: 794px) 100vw, 794px\" \/><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">If a recipient has a spam filter that checks email components (subject lines, email content, any emails that don't meet the spam filter criteria will be blocked.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">If the recipient\u2019s email server has a policy to block emails from certain sender IP addresses or domains, emails will be automatically rejected.<\/span><\/li>\n<\/ul>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\">\n<p><b>How to fix:<\/b><span style=\"font-weight: 400;\"> Emails can be blocked for various reasons. Check the error description in the bounce report.\u00a0<\/span><\/p>\n<p><a href=\"https:\/\/snov.io\/knowledgebase\/how-to-avoid-spam-filters\/\" target=\"_blank\" rel=\"noopener\">Read tips and advice on how to pass through spam filters \u2192\u00a0<\/a><\/p>\n<\/div>\n<\/div>\n<h3><strong>Soft bounces<\/strong><\/h3>\n<p>Soft bounce is a temporary delivery error <span style=\"font-weight: 400;\">and the email might still be delivered successfully after you fix the issue or retry.\u00a0<\/span><\/p>\n<p><b>1) Message not delivered: <\/b><span style=\"font-weight: 400;\">When the recipient's server isn\u2019t able to accept the email.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This delivery error happens due to a temporary server error or connection timeout while sending the email.\u00a0<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-block-image shadow aligncenter wp-image-26504 \" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.not_.delivered.png\" alt=\"\" width=\"801\" height=\"240\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.not_.delivered.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.not_.delivered-300x90.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/message.not_.delivered-768x230.png 768w\" sizes=\"(max-width: 801px) 100vw, 801px\" \/><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><strong><b>How to fix: <\/b><span style=\"font-weight: 400;\">The issue is with the recipient's email server and will typically resolve itself. Check the error details in your inbox and try resending the email later.<\/span><\/strong><\/div>\n<\/div>\n<p><b>2) Recipient inbox full<\/b><\/p>\n<p><span style=\"font-weight: 400;\">It happens when there is no more space in the recipient's email client for new incoming emails or when it receives too many emails at the same time.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-block-image shadow aligncenter wp-image-26505 \" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/inbox.full_.png\" alt=\"\" width=\"801\" height=\"240\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/inbox.full_.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/inbox.full_-300x90.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/inbox.full_-768x230.png 768w\" sizes=\"(max-width: 801px) 100vw, 801px\" \/><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><b>How to fix: <\/b><span style=\"font-weight: 400;\">The delivery will be successful once there\u2019s a free space in the inbox. Retry sending the email after some time.<\/span><\/div>\n<\/div>\n<p><b>3) Delivery incomplete: <\/b><span style=\"font-weight: 400;\">When the recipient's server is temporarily down or unavailable.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Like the \"Message not delivered\" error, emails cannot be delivered if the recipient's server doesn't respond.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-block-image shadow aligncenter wp-image-26506 \" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/incomplete.png\" alt=\"\" width=\"808\" height=\"242\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/incomplete.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/incomplete-300x90.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2019\/09\/incomplete-768x230.png 768w\" sizes=\"(max-width: 808px) 100vw, 808px\" \/><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><b>How to fix: <\/b><span style=\"font-weight: 400;\">This delivery error is temporary, and the only solution is to wait until the recipient's server is able to accept emails again.\u00a0<\/span><\/div>\n<\/div>\n<p><span style=\"font-weight: 400;\">Usually, your email provider will try to resend the email automatically a few times.<\/span><\/p>\n<p><b>4) The daily sending limit exceeded<\/b><\/p>\n<p><span style=\"font-weight: 400;\">This delivery error happens when you reach the daily\/hourly sending limit set by your email provider.<\/span><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><b>How to fix:<\/b><span style=\"font-weight: 400;\"> You should be able to send emails again within 1 to 24 hours when your daily limit is reset.<\/span><\/div>\n<\/div>\n<p><b>5) Email size is too large<\/b><\/p>\n<p><span style=\"font-weight: 400;\">Your email exceeds the maximum size limit allowed by the recipient's email server.<\/span><\/p>\n<div class=\"notification-block tip\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/academicons_ideas-repec.svg\" alt=\"tip\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><b>How to fix: <\/b><span style=\"font-weight: 400;\">If your email contains multiple images or graphics, make sure to compress them to reduce their size or remove any excessive content.<\/span><\/div>\n<\/div>\n<h2 id=\"prevent-bounced-emails\"><strong>How to prevent bounced emails<\/strong><\/h2>\n<p>Lots of bounced emails can really damage your reputation as a sender. Make sure to handle it right to avoid harming your deliverability and campaign results.<\/p>\n<p><strong>1) Verify emails before launching campaigns<\/strong><\/p>\n<p>Use the built-in <a href=\"https:\/\/snov.io\/email-verifier\" target=\"_blank\" rel=\"noopener\">email verifier<\/a> tool to check emails in your list before starting campaigns. Unverified emails have a much higher chance of resulting in delivery errors.<\/p>\n<p><strong>2)<\/strong><b> Take care of your sender reputation\u00a0<\/b><\/p>\n<p><span style=\"font-weight: 400;\">The root cause of many bounces is a low sender reputation, which causes receiving email servers to reject emails.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A low sender reputation is caused by factors such as poor engagement, high complaint rates (when recipients report emails as spam), and a lack of domain configuration.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Learn <\/span><a href=\"https:\/\/snov.io\/knowledgebase\/how-to-increase-reply-rate-with-email-best-practices\/\">Email best practices<\/a><span style=\"font-weight: 400;\"> \u2192 to improve your reply rate, one of the main metrics for better sender reputation and campaign success.<\/span><\/p>\n<p><strong>3) Setup your sender domain<\/strong><\/p>\n<p>Email service providers also check authentication to evaluate senders' reputations. Emails that fail authentication checks may also bounce.<\/p>\n<p><span style=\"font-weight: 400;\">To authenticate your emails, set up <a href=\"https:\/\/snov.io\/knowledgebase\/set-up-spf-record-for-your-domain\/\" target=\"_blank\" rel=\"noopener\">SPF<\/a>, <a href=\"https:\/\/snov.io\/knowledgebase\/set-up-dkim-for-your-domain\/\" target=\"_blank\" rel=\"noopener\">DKIM<\/a>, and <a href=\"https:\/\/snov.io\/knowledgebase\/set-up-dmarc-policy-for-your-domain\/\" target=\"_blank\" rel=\"noopener\">DMARC<\/a> records in your domain\u2019s settings.<\/span><\/p>\n<p><strong>4)<\/strong><b> Test emails before sending campaigns<\/b><\/p>\n<p>With Snov.io\u2019s Deliverability check, you can troubleshoot and fix various issues that affect your inbox placement.<\/p>\n<p>You can also check your sender domain settings (DNS records) and make sure your email content follows the recommended practices.<\/p>\n<p>Go to the <a href=\"https:\/\/app.snov.io\/deliverability#\/check\"><b>Deliverability check page.<\/b><\/a><b> <\/b>Click\u00a0<b>Get started\u00a0<\/b>and create a test.<\/p>\n<p>If you have a question that we haven't covered, feel free to reach out to our Customer Care team. You can contact us at help@snov.io or through live chat. We're here to assist you!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This article explains hard and soft bounces, common delivery errors in cold email automation, why they occur, and how to fix them. Bounces are email delivery errors that occur when emails fail to reach their intended recipients and are returned to your inbox. Email bounce types &#8211;&gt; Prevent bounced emails &#8211;&gt; Before we start, here [&hellip;]<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1966],"tags":[],"_links":{"self":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/531"}],"collection":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/comments?post=531"}],"version-history":[{"count":4,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/531\/revisions"}],"predecessor-version":[{"id":38472,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/531\/revisions\/38472"}],"wp:attachment":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/media?parent=531"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/categories?post=531"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/tags?post=531"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}