diff --git a/lms/djangoapps/bulk_email/tasks.py b/lms/djangoapps/bulk_email/tasks.py
index d6b8393f470e..4d86edcc103e 100644
--- a/lms/djangoapps/bulk_email/tasks.py
+++ b/lms/djangoapps/bulk_email/tasks.py
@@ -10,7 +10,7 @@
 import time
 from collections import Counter
 from datetime import datetime
-from smtplib import SMTPConnectError, SMTPDataError, SMTPException, SMTPServerDisconnected
+from smtplib import SMTPConnectError, SMTPDataError, SMTPException, SMTPServerDisconnected, SMTPSenderRefused
 from time import sleep
 
 from boto.exception import AWSConnectionError
@@ -87,12 +87,13 @@
 # An example is if email is being sent too quickly, but may succeed if sent
 # more slowly.  When caught by a task, it triggers an exponential backoff and retry.
 # Retries happen continuously until the email is sent.
-# Note that the SMTPDataErrors here are only those within the 4xx range.
+# Note that the (SMTPDataErrors and SMTPSenderRefused)  here are only those within the 4xx range.
 # Those not in this range (i.e. in the 5xx range) are treated as hard failures
 # and thus like SINGLE_EMAIL_FAILURE_ERRORS.
 INFINITE_RETRY_ERRORS = (
     SESMaxSendingRateExceededError,  # Your account's requests/second limit has been exceeded.
     SMTPDataError,
+    SMTPSenderRefused,
 )
 
 # Errors that are known to indicate an inability to send any more emails,
@@ -565,11 +566,11 @@ def _send_course_email(entry_id, email_id, to_list, global_email_context, subtas
                     f"{recipient_num}/{total_recipients}, Recipient UserId: {current_recipient['pk']}"
                 )
                 message.send()
-            except SMTPDataError as exc:
+            except (SMTPDataError, SMTPSenderRefused) as exc:
                 # According to SMTP spec, we'll retry error codes in the 4xx range.  5xx range indicates hard failure.
                 total_recipients_failed += 1
                 log.exception(
-                    f"BulkEmail ==> Status: Failed(SMTPDataError), Task: {parent_task_id}, SubTask: {task_id}, "
+                    f"BulkEmail ==> Status: Failed({exc.smtp_error}), Task: {parent_task_id}, SubTask: {task_id}, "
                     f"EmailId: {email_id}, Recipient num: {recipient_num}/{total_recipients}, Recipient UserId: "
                     f"{current_recipient['pk']}"
                 )
diff --git a/lms/djangoapps/bulk_email/tests/test_tasks.py b/lms/djangoapps/bulk_email/tests/test_tasks.py
index 51f7b4161c88..e73db046aab8 100644
--- a/lms/djangoapps/bulk_email/tests/test_tasks.py
+++ b/lms/djangoapps/bulk_email/tests/test_tasks.py
@@ -11,7 +11,7 @@
 from dateutil.relativedelta import relativedelta
 import json  # lint-amnesty, pylint: disable=wrong-import-order
 from itertools import chain, cycle, repeat  # lint-amnesty, pylint: disable=wrong-import-order
-from smtplib import SMTPAuthenticationError, SMTPConnectError, SMTPDataError, SMTPServerDisconnected  # lint-amnesty, pylint: disable=wrong-import-order
+from smtplib import SMTPAuthenticationError, SMTPConnectError, SMTPDataError, SMTPServerDisconnected, SMTPSenderRefused  # lint-amnesty, pylint: disable=wrong-import-order
 from unittest.mock import Mock, patch  # lint-amnesty, pylint: disable=wrong-import-order
 from uuid import uuid4  # lint-amnesty, pylint: disable=wrong-import-order
 import pytest
@@ -411,6 +411,11 @@ def _test_retry_after_unlimited_retry_error(self, exception):
     def test_retry_after_smtp_throttling_error(self):
         self._test_retry_after_unlimited_retry_error(SMTPDataError(455, "Throttling: Sending rate exceeded"))
 
+    def test_retry_after_smtp_sender_refused_error(self):
+        self._test_retry_after_unlimited_retry_error(
+            SMTPSenderRefused(421, "Throttling: Sending rate exceeded", self.instructor.email)
+        )
+
     def test_retry_after_ses_throttling_error(self):
         self._test_retry_after_unlimited_retry_error(
             SESMaxSendingRateExceededError(455, "Throttling: Sending rate exceeded")