diff --git a/logdna/logdna.py b/logdna/logdna.py
index a430a2d..7597f45 100644
--- a/logdna/logdna.py
+++ b/logdna/logdna.py
@@ -212,8 +212,10 @@ def send_request(self, data):  # noqa: max-complexity: 13
                     3XX                       unexpected status
                     401, 403                  expected client error,
                                               invalid ingestion key
+                    429                       expected server error,
+                                              "client error", transient
                     4XX                       unexpected client error
-                    500 502 503 507           expected server error, transient
+                    500 502 503 504 507       expected server error, transient
                     5XX                       unexpected server error
                 handling:
                     expected status           discard flush buffer
@@ -256,6 +258,14 @@ def send_request(self, data):  # noqa: max-complexity: 13
                         'Error Response: %s', response.text)
                 return True  # discard
 
+            if status_code == 429:
+                self.internalLogger.debug('Client Error: %s. Retrying...',
+                                          reason)
+                if self.log_error_response:
+                    self.internalLogger.debug(
+                        'Error Response: %s', response.text)
+                return False  # retry
+
             if 400 <= status_code <= 499:
                 self.internalLogger.debug('Client Error: %s. ' +
                                           'Discarding flush buffer',
@@ -265,7 +275,7 @@ def send_request(self, data):  # noqa: max-complexity: 13
                         'Error Response: %s', response.text)
                 return True  # discard
 
-            if status_code in [500, 502, 503, 507]:
+            if status_code in [500, 502, 503, 504, 507]:
                 self.internalLogger.debug('Server Error: %s. Retrying...',
                                           reason)
                 if self.log_error_response:
diff --git a/tests/test_logger.py b/tests/test_logger.py
index bb177e2..6ee1a08 100644
--- a/tests/test_logger.py
+++ b/tests/test_logger.py
@@ -171,7 +171,49 @@ def test_try_request_500(self):
         with patch('requests.post') as post_mock:
             r = requests.Response()
             r.status_code = 500
-            r.reason = 'OK'
+            r.reason = 'Internal Server Error'
+            post_mock.return_value = r
+            handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)
+            sample_message['timestamp'] = unittest.mock.ANY
+            handler.buf = [sample_message]
+            handler.try_request()
+            self.assertTrue(handler.exception_flag)
+            self.assertTrue(post_mock.call_count, 3)
+
+    @mock.patch('time.time', unittest.mock.MagicMock(return_value=now))
+    def test_try_request_502(self):
+        with patch('requests.post') as post_mock:
+            r = requests.Response()
+            r.status_code = 502
+            r.reason = 'Bad Gateway'
+            post_mock.return_value = r
+            handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)
+            sample_message['timestamp'] = unittest.mock.ANY
+            handler.buf = [sample_message]
+            handler.try_request()
+            self.assertTrue(handler.exception_flag)
+            self.assertTrue(post_mock.call_count, 3)
+
+    @mock.patch('time.time', unittest.mock.MagicMock(return_value=now))
+    def test_try_request_504(self):
+        with patch('requests.post') as post_mock:
+            r = requests.Response()
+            r.status_code = 504
+            r.reason = 'Gateway Timeout'
+            post_mock.return_value = r
+            handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)
+            sample_message['timestamp'] = unittest.mock.ANY
+            handler.buf = [sample_message]
+            handler.try_request()
+            self.assertTrue(handler.exception_flag)
+            self.assertTrue(post_mock.call_count, 3)
+
+    @mock.patch('time.time', unittest.mock.MagicMock(return_value=now))
+    def test_try_request_429(self):
+        with patch('requests.post') as post_mock:
+            r = requests.Response()
+            r.status_code = 429
+            r.reason = 'Too Many Requests'
             post_mock.return_value = r
             handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)
             sample_message['timestamp'] = unittest.mock.ANY
@@ -185,7 +227,7 @@ def test_try_request_403(self):
         with patch('requests.post') as post_mock:
             r = requests.Response()
             r.status_code = 403
-            r.reason = 'OK'
+            r.reason = 'Forbidden'
             post_mock.return_value = r
             handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)
             sample_message['timestamp'] = unittest.mock.ANY
@@ -199,7 +241,7 @@ def test_try_request_403_log_response(self):
         with patch('requests.post') as post_mock:
             r = requests.Response()
             r.status_code = 403
-            r.reason = 'OK'
+            r.reason = 'Forbidden'
             post_mock.return_value = r
             sample_options['log_error_response'] = True
             handler = LogDNAHandler(LOGDNA_API_KEY, sample_options)