Understanding email delivery failures in the Zendesk Agent Workspace

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<p id="docs-ai-summary-content">In the Agent Workspace, you can identify email delivery failures and troubleshoot them using error codes and messages. Learn best practices for resolving issues like invalid addresses or full inboxes, and understand how tickets with delivery failures are tagged. View error messages in the ticket interface and events log to manage and resolve email delivery problems effectively.</p>
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<div class="p">
<div class="note" id="zug_email_delivery_status__note_d5l_bsk_h2c">
<span class="notetitle">Note:</span> This feature doesn't apply to email sent through the <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408835030426" target="_blank">Gmail connector</a>, <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/6740880198810" target="_blank">authenticated SMTP connector</a>, or email notifications
sent without ticket comments.</div>
</div>
<p class="p">Email notifications and email-based conversations form the backbone of customer service
interactions in Zendesk. Your customers typically receive messages from and respond to
agents through threaded email replies. If email messages aren't successfully delivered,
it can significantly hamper your ability to assist customers effectively.</p>
<p class="p">Email delivery issues may occur for several reasons, such as an invalid email address,
the recipient's inbox being full, or the email mistakenly detected as spam by the
recipient's mail server. In the Agent Workspace, agents can identify if outbound email
delivery failures have occurred. Warning messages provide information about which
recipient didn't receive the email and why, including specific error codes to help
troubleshoot the problem. Zendesk reports delivery failures that it has visibility into.
Zendesk can confirm successful email handoff for delivery, but the final delivery to the
recipient is outside its control and scope of visibility.</p>
<p class="p">This article includes the following topics:</p>
<ul class="ul" id="zug_email_delivery_status__ul_g3w_zkd_rcc">
<li class="li"><a class="xref" href="#topic_eyq_wb3_qcc">Agent best practices for resolving email delivery issues</a></li>
<li class="li"><a class="xref" href="#topic_qw5_m3s_tgc">Understanding how tickets with email delivery failures are tagged</a></li>
<li class="li"><a class="xref" href="#topic_tzn_g13_qcc">Viewing email delivery failure messages in the ticket interface</a></li>
<li class="li"><a class="xref" href="#topic_kvw_k2l_rcc">Viewing email delivery failure messages in the ticket events log</a></li>
</ul>
<div class="p">Related articles:<ul class="ul" id="zug_email_delivery_status__ul_lhf_fmf_fgc">
<li class="li"><a class="xref" href="https://developer.zendesk.com/api-reference/ticketing/tickets/email_notifications/#delivery-status-reference" target="_blank">Email Notifications: Delivery Status
Reference</a></li>
</ul>
</div>
</div>
<div aria-labelledby="ariaid-title2" class="topic nested1" id="topic_eyq_wb3_qcc">
<h2 class="title topictitle2" id="ariaid-title2">Agent best practices for resolving email delivery issues</h2>
<div class="body">
<p class="p">Agents can take the following actions when they see delivery failures in the Agent
Workspace:</p>
<ul class="ul" id="topic_eyq_wb3_qcc__ul_jfp_35d_rcc">
<li class="li">If an error code is provided with the failure message, you can use online
resources such as Google or an AI tool for a detailed explanation, as these
codes are industry-standard SMTP codes that are not defined by Zendesk. You can
also refer to the <a class="xref" href="https://developer.zendesk.com/api-reference/ticketing/tickets/email_notifications" target="_blank">error code reference</a> in the developer
documentation for a summary of the specific issue.</li>
<li class="li">If the error indicates the email address is invalid or doesn't exist, <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408822762650" target="_blank">check the email address</a> on the end
user's profile for typos.</li>
<li class="li">If the error indicates a problem that the end user can solve (for example, the
mailbox is full or doesn't exist), contact the user using another method to
notify them and obtain a different email address.</li>
<li class="li">If you can solve the problem (for example, the message is too big), make
adjustments, and re-send the email by <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408828489370" target="_blank">adding a public comment</a> to the
ticket.</li>
</ul>
</div>
</div>
<div aria-labelledby="ariaid-title3" class="topic nested1" id="topic_qw5_m3s_tgc">
<h2 class="title topictitle2" id="ariaid-title3">Understanding how tickets with email delivery failures are tagged</h2>
<div class="body">
<p class="p">The <strong class="ph b">system_email_notification_failure</strong>
<a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408835059482" target="_blank">ticket tag</a> is added to tickets with
outbound email delivery failures, allowing you to create views and search for these
tickets.</p>
<ul class="ul" id="topic_qw5_m3s_tgc__ul_bqd_tjs_tgc">
<li class="li">The tag may appear up to five days after the email notification was initially
sent. This is because if the server response indicates a temporary error,
Zendesk may retry sending the email periodically up to five days.</li>
<li class="li">Zendesk will attempt to add the tag every time an email fails to send. If the
tag is already present from an earlier failure, you will not see a new ticket
event for it.</li>
</ul>
</div>
</div>
<div aria-labelledby="ariaid-title4" class="topic nested1" id="topic_tzn_g13_qcc">
<h2 class="title topictitle2" id="ariaid-title4">Viewing email delivery failure messages in the ticket interface</h2>
<div class="body">
<p class="p">Error messages will appear below the ticket comments in the conversation log. </p>
<div class="note" id="topic_tzn_g13_qcc__note_inf_2rk_h2c">
<span class="notetitle">Note:</span> Error messages don't display in the To/CCs section for email
notifications sent via the <strong class="ph b">Notify by &gt; User email | Ticket &gt; (requester)</strong>
trigger action. This is because the To/CCs section is always hidden for these
emails.</div>
<div class="p">
<strong class="ph b">To view email delivery failure messages in the ticket interface</strong><ul class="ul" id="topic_tzn_g13_qcc__ul_p2n_zpv_g2c">
<li class="li">In a ticket, view any error messages below the ticket conversation.</li>
</ul>
</div>
<p class="p"><img class="image img-screenshot" id="topic_tzn_g13_qcc__image_qq2_5dl_rcc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_convo_log_expanded.png" width="400"></p>
<p class="p">Optionally click the warning icon (<img class="image img-screenshot" id="topic_tzn_g13_qcc__image_yt2_g1k_rcc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_warning_icon.png" width="20">) next to a
user's name to view the reason for the failure and the associated error code for the
recipient, if applicable. This feature is beneficial when multiple recipients are on
the ticket, or several delivery failures exist.</p>
<p class="p">Error messages differ slightly, depending on whether failures occurred for a single
or multiple recipients, or if there's more than one type of failure.</p>
<div class="p">The examples below help illustrate the types of messages agents may see in
tickets:<ul class="ul" id="topic_tzn_g13_qcc__ul_akn_12k_rcc">
<li class="li"><a class="xref" href="#topic_szb_nph_scc">Failed to deliver email to one recipient</a></li>
<li class="li"><a class="xref" href="#topic_e51_l1d_rcc">Failed to deliver email to all recipients</a></li>
<li class="li"><a class="xref" href="#topic_tjd_4cd_rcc">Failed to deliver email to some recipients</a></li>
</ul>
</div>
</div>
<div aria-labelledby="ariaid-title5" class="topic nested2" id="topic_szb_nph_scc">
<h3 class="title topictitle3" id="ariaid-title5">Failed to deliver email to one recipient</h3>
<div class="body">
<p class="p">When an email has failed to deliver to one recipient, the error message and code
(if applicable) appear under the ticket comment.</p>
<p class="p"><img class="image img-screenshot" id="topic_szb_nph_scc__image_qll_pph_scc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_convo_log_single_new.png" width="400"></p>
</div>
</div>
<div aria-labelledby="ariaid-title6" class="topic nested2" id="topic_e51_l1d_rcc">
<h3 class="title topictitle3" id="ariaid-title6">Failed to deliver email to all recipients</h3>
<div class="body">
<p class="p">When an email has failed to deliver to all (multiple) recipients, a <strong class="ph b">Failed to
deliver</strong> message appears under the ticket comment. Click the warning icon
(<img class="image img-screenshot" id="topic_e51_l1d_rcc__image_omw_nfl_rcc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_warning_icon.png" width="20">) next to a
user's name to view the reason for the failure and the associated error code for
the recipient, if applicable.</p>
<p class="p"><img class="image img-screenshot" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_failed_multiple_convo.png" width="400"></p>
</div>
</div>
<div aria-labelledby="ariaid-title7" class="topic nested2" id="topic_tjd_4cd_rcc">
<h3 class="title topictitle3" id="ariaid-title7">Failed to deliver email to some recipients</h3>
<div class="body">
<p class="p">When the delivery fails for only some recipients, the <strong class="ph b">Failed to deliver to
some recipients</strong> message appears. Warning icons (<img class="image img-screenshot" id="topic_tjd_4cd_rcc__image_dwr_vfl_rcc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_warning_icon.png" width="20">) only
appear next to the names of the recipients with delivery failures. Click the
warning icon next to a user's name to view the reason for the failure and the
associated error code for the recipient, if applicable.</p>
<p class="p"><img class="image img-screenshot" id="topic_tjd_4cd_rcc__image_fqs_5kd_rcc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_some_recipients_new.png" width="400"></p>
</div>
</div>
</div>
<div aria-labelledby="ariaid-title8" class="topic nested1" id="topic_kvw_k2l_rcc">
<h2 class="title topictitle2" id="ariaid-title8">Viewing email delivery failure messages in the ticket events log</h2>
<div class="body">
<p class="p">The <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408829602970" target="_blank">ticket events log</a> includes a history of
email delivery failures for a ticket. The failure messages shown in ticket events
are similar to those in the conversation log. The <strong class="ph b">Email notification</strong> section
lists the triggers associated with the failures. </p>
<div class="p">
<strong class="ph b">To view email delivery failure messages in the ticket events log</strong><ul class="ul" id="topic_kvw_k2l_rcc__ul_u2b_3pv_g2c">
<li class="li">Click the events icon ( <img class="image" id="topic_kvw_k2l_rcc__image_u3b_vlh_3mb" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/uc_events_icon.png">) in the <a class="xref" href="https://support.zendesk.com/hc/en-us/articles/4408823962906#topic_n4m_fyc_zlb" target="_blank">conversation header</a> to open the
ticket events log, then view the error message below the ticket event.</li>
</ul>
</div>
<img class="image img-screenshot" id="topic_kvw_k2l_rcc__image_nkc_b3h_scc" src="https://zen-marketing-documentation.s3.amazonaws.com/docs/en/email_status_failure_some_recipients_trigger_new.png" width="400">
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