Why Emails Bounce?

Email bounces happen to everyone all the time. It’s completely normal; in most cases, it doesn’t mean you’ve made a mistake. Yet, it’s crucial to understand why they bounce. Email networks monitor your bounce rate, and they will refuse to receive your future emails if it is too high (>5%).

Let’s talk about the possible reasons for your emails to bounce. We need to define the three types of bounces: soft, hard, and blocklist.

Soft bounce

By saying that emails soft bounce, we mean that the receiving server rejects them temporarily. It can happen due to a full inbox on the recipient’s side, an autoreply setting turned on, your email being too heavy on attachments or images, or server maintenance.That is a no-worries case: you will be able to send your email to them later.

Hard bounce

A hard bounce means that the email will not be delivered at all. It usually happens when the recipient’s address is either fake or misspelled or if the recipient blocked your email. It happens, and unfortunately, there’s nothing you can do about it.What you can do is remove addresses that hard bounce from your list. This way, you will reduce the number of bounces in the future.

Blocklist

If your email address was blocklisted, the ISP considered it spam or malware. There can be a plethora of reasons for that. One of them we mentioned earlier: if your bounce rateis high, the receiving servers will keep bouncing your emails in the future. Spam complaints or questionable content can be another reason - you can read more about it in our article here. Finally, the service may have detected a sudden surge in your sending volume. It’s a signal that you bought a contact list, which implies that you send spam.Fortunately, you can get off blocklists - we described the necessary steps in a separate guide. In the guide, you can also learn what to do with soft and hard bounces.