How do bounces and phishing attacks affect email deliverability and domain reputation?

Email marketer from Email Geeks shares that some antispam systems bounce emails based on indicators (including false positives) and may track repeated sending attempts, which influences deliverability. The impact varies depending on the MBPs.

Email marketer from TalosIntelligence explains that a high percentage of bad addresses can negatively affect sender reputation, leading to email blocking or spam filtering. High bounce rates are a sign of outdated or poorly maintained email lists.

Email marketer from Email on Acid explains that soft bounces can indicate temporary issues, but repeated soft bounces or a high volume of them can still damage your sender reputation over time. Hard bounces should be immediately removed from your list.

Email marketer from Litmus explains that if your domain is used in phishing attacks, it can be blacklisted, severely harming your sender reputation and deliverability.

Email marketer from SparkPost explains that domain reputation is affected by hard bounces and spam traps. Poor domain reputation negatively affects inbox placement.

Email marketer from SendGrid shares that excessive bounces indicate poor list hygiene and negatively affect sender reputation, leading to deliverability problems. They also share that phishing activity will lead to your domain to be blacklisted, decreasing email deliverability.

Email marketer from Reddit explains that ISPs use bounce rates as a key metric to assess sender reputation. A high bounce rate suggests you're either sending to outdated lists or engaging in spammy practices, both of which hurt your ability to reach the inbox.

Email marketer from GlockApps explains that email list hygiene has an effect on deliverability and sender reputation. It's important to clean up bounced emails and also maintain that list to prevent your account from being flagged as a spammer.

Email marketer from Validity explains that domain reputation is tied to how mailbox providers view your email program, and is affected by metrics like spam complaints, bounce rates, and blocklist status.

Email marketer from Email Geeks explains that each MBP will treat bounces differently. Some bounces have more impact to deliverability such as invalid rcpts.

Email marketer from ZeroBounce explains that hard bounces have the potential to harm sender reputation. Poor sender reputation negatively impacts email deliverability. Regular removal of hard bounces is key.

Email marketer from Email Geeks shares that Sendgrid's suppression list work in mysterious ways. They actually drop your bounces for your next outgoing mail streams, but don't do any kind of drops or implement additional rules on 'Blocks'.

Email marketer from Mailjet explains that hard bounces signal invalid email addresses, which significantly damages sender reputation. Email Service Providers (ESPs) interpret high hard bounce rates as a sign of poor list hygiene, leading to reduced deliverability. They also recommend that phishing can get your IP address and Domain blacklisted.

Expert from Email Geeks considers attempts to mail to bad addresses a negative delivery factor. Also some others that are going to affect reputation.

Expert from Email Geeks suggests investigating high bounces, as trying to deliver to non-existent addresses negatively impacts reputation.

Expert from Email Geeks shares that the domain is being heavily abused through forgeries, impacting overall domain reputation, even if DMARC is in place, affecting deliverability.

Expert from Email Geeks shares to take out any addresses that failed to deliver with a ‘user unknown’ - basically adding them to the suppression list. A 550 user unknown is (in the vast majority of cases) a sign that the address is not in use and should be removed from the list

Expert from Email Geeks notes that there is a lot of phishing related to WeTransfer, and recommends that machine learning filters and manual filters might be wary of emails that mention WeTransfer.

Expert from Email Geeks recommends not using noreply@wetransfer.com as the sending address for newsletters due to its heavy use in phishing, and to clearly separate marketing newsletters.

Expert from Email Geeks explains that temporary failures in the bounce report don’t directly affect your reputation, but they indicate underlying reputation issues that need attention.

Expert from Email Geeks notes that cleansing isn’t going to really affect deliverability.

Expert from Word to the Wise explains that hitting spam traps negatively affects your sending reputation, and high bounce rates are indicative of poor list hygiene, also affecting reputation and deliverability. They note that while not exactly a 'bounce,' hitting a trap can have similar or worse repercussions.

Expert from Spamresource explains that participating in or enabling phishing activity, or not handling bounces properly can result in being blacklisted, which has an immediate negative impact on deliverability.

Documentation from Gmail Help explains that high bounce rates can negatively impact your sender reputation. They recommend keeping bounce rates below 5% and using feedback loops to identify campaigns causing issues. Phishing attempts originating from or impersonating your domain will lead to your domain being blacklisted, severely affecting deliverability to Gmail users.

Documentation from DMARC.org explains that DMARC is an email authentication protocol that helps prevent phishing and spoofing. Implementing DMARC allows domain owners to instruct receiving mail servers on how to handle emails that fail authentication checks, protecting their brand and reputation.

Documentation from IETF details that SPF records assist in preventing sender address forgery, which is a key component of phishing attacks. Implementing SPF helps protect your domain's reputation.

Documentation from RFC explains that understanding SMTP error codes helps diagnose bounce issues. Specifically, 5xx errors (permanent failures) negatively impact sender reputation more than 4xx errors (temporary failures).

Documentation from Microsoft explains that a high volume of phishing complaints will cause your emails to be routed to the junk folder, and eventually blocked. Also, high bounce rates are an indicator of poor sending practices, which results in filtering.