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Delivered, Bounced, Blocked, and Deferred Emails

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Great email entrepreneurs are at all times discovering methods to inform extra compelling tales with their information. Stories, you ask? Yes, your information tells an awesome many tales that may enable you, the sender, perceive what’s taking place along with your email campaigns.

Are individuals registering too many spam complaints? Are my open charges altering? Why are so many individuals opting out of my messages? The information you get again while you ship a marketing campaign, and the questions these information factors increase, are the beginning factors for understanding what story your outcomes let you know.

Naturally, information factors resembling opens and spam complaints let you know fairly a bit about how recipients work together along with your messages. However, there are vital occasions within the journey of your message which can be simply as significant and are sometimes missed by entrepreneurs.

When you ship an email to your subscribers through Twilio SendGrid, there are actually only some issues that may occur to that message between SendGrid and the receiving server. Those occasions are:

  • Delivered: The receiving server accepted the message
  • Bounce: The receiving server denied the message and the tackle despatched to is suppressed by SendGrid shifting ahead
  • Blocked: The receiving server denied the message and the tackle isn’t suppressed by SendGrid shifting ahead
  • Deferred: The receiving server delayed acceptance of the message

Let’s take a fast take a look at what every of these occasions means that will help you glean a greater image of your email supply efficiency.


A standard false impression that I typically run into is {that a} delivered message is a message that made it to the inbox. When a message registers as delivered, that merely means the receiving server has accepted the message from SendGrid. At that time, the receiving server nonetheless has to determine what to do with that message.

Most typically, the two choices going through that server are to ship the message to the meant inbox or to ship it to the spam or junk folder. Less incessantly, a receiving server may select to easily drop that message, which is akin to the receiving server merely deleting it. In these circumstances, the recipient received’t be capable to discover the message, even when they search for it of their spam folder. Dropping a message is uncommon, although it may possibly occur.

Almost at all times, the choice about the place to place the message comes right down to the sending popularity of the sender and the content material despatched. Senders who generate extreme spam complaints from recipients, or senders sending content material recognized by inbox suppliers to generate excessive charges of spam complaints, are more likely to see their emails not make the inbox. Having a excessive proportion of delivered emails is nice. However, merely getting emails delivered is barely a part of email success.


While some within the business use phrases like “hard bounce” and “soft bounce” to explain messages refused by the receiving server, SendGrid’s terminology separates returned messages into bounces and blocks.

Bounces happen when the receiving server returns to us a code that signifies that the rationale for the refusal is a everlasting concern with that server or recipient tackle. The commonest purpose an tackle will bounce is that the tackle in query isn’t legitimate. If you’re utilizing SendGrid’s Event Webhook to digest your email occasions, a bounce can be beneath the bounce occasion with the kind “bounce.”


Similar to what you might have heard known as a “soft bounce,” blocked emails are ones the place the receiving server returned to us a purpose for refusal that signifies a nonpermanent rejection for that tackle. In brief, it’s a rejection of that message and not a sign of the standard of the despatched to deal with.

Common causes a message is likely to be blocked are in case your sending IP or area has been record denied, the content material of your marketing campaign incorporates components the inbox supplier deems “spammy,” or there was a technical concern that occurred between the two servers on the time you tried to ship the marketing campaign.

While elevated charges of spam complaints will imply extra emails filtered to the spam folder, these may lead to blocks as a consequence of a poor sending popularity. With SendGrid’s Event Webhook, blocks are recognized by the bounce occasion beneath the kind “blocked.” Seeing a number of blocked messages is an effective indicator that your sending popularity is likely to be struggling.


A deferred occasion, or deferral, is solely an occasion SendGrid has obtained again from the receiving server that tells us that the receiving server has briefly restricted entry to their system. If you’re like me and sufficiently old to recollect life earlier than name ready and cell telephones, you’ll be able to consider this like a busy sign.

It doesn’t imply that your message is not going to be delivered. Rather, it’s a sign that your message is not going to be delivered instantly. This can occur for quite a lot of causes. Some of the most typical causes a message is likely to be deferred at an inbox supplier are that the inbox supplier is seeing too many spam complaints in your email that has already been delivered or the receiving server is having technical points at the moment.

When SendGrid sees your mail being deferred at a specific inbox supplier, we’ll proceed to attempt to ship that message for you for as much as 72 hours. If a message to a recipient is deferred for greater than 72 hours, that deferral will flip right into a block. Otherwise, it’ll lead to a supply occasion as soon as the message has been accepted by the receiving server.

Get assist delivering to the inbox with Twilio SendGrid

Keeping an eye fixed on these occasions can provide you much more perception into what is occurring along with your emails as they journey from Twilio SendGrid to the recipient’s inbox. If you’d wish to dive deeper into your email supply well being, take a look at our Email Deliverability Guide.

And in case you’re utilizing SendGrid’s Event Webhook to digest your information, we’ve got some nice data in our documentation on the completely different occasions you’ve entry to in our documentation.

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