diff --git a/doc/Command-Reference.md b/doc/Command-Reference.md
index 689ca23b73..5625b04eab 100644
--- a/doc/Command-Reference.md
+++ b/doc/Command-Reference.md
@@ -3109,11 +3109,15 @@ This command is the standard CMIS diagnostic control used for troubleshooting li
   sfputil debug loopback PORT_NAME LOOPBACK_MODE
 
   Set the loopback mode
-  host-side-input: host side input loopback mode
-  host-side-output: host side output loopback mode
-  media-side-input: media side input loopback mode
-  media-side-output: media side output loopback mode
-  none: disable loopback mode
+  host-side-input: enable host side input loopback mode
+  host-side-output: enable host side output loopback mode
+  media-side-input: enable media side input loopback mode
+  media-side-output: enable media side output loopback mode
+  host-side-input-none: disable host side input loopback mode
+  host-side-output-none: disable host side output loopback mode
+  media-side-input-none: disable media side input loopback mode
+  media-side-output-none: disable media side output loopback mode
+  none: disable all loopback mode
   ```
 
 - Example:
diff --git a/sfputil/main.py b/sfputil/main.py
index 992db42ac9..004a47ea9f 100644
--- a/sfputil/main.py
+++ b/sfputil/main.py
@@ -1997,28 +1997,39 @@ def loopback(port_name, loopback_mode):
     config_db = ConfigDBConnector(use_unix_socket_path=True, namespace=namespace)
     if config_db is not None:
         config_db.connect()
-        subport = int(config_db.get(config_db.CONFIG_DB,
-                                    'PORT|{}'.format(port_name), 'subport'))
+        try:
+            subport = int(config_db.get(config_db.CONFIG_DB, f'PORT|{port_name}', 'subport'))
+        except TypeError:
+            click.echo(f"{port_name}: subport is not present in CONFIG_DB")
+            sys.exit(EXIT_FAIL)
 
-        # If subport is not defined (None) or set to 0, assign a default value of 1
-        # to ensure valid subport configuration.
-        if subport is None or subport == 0:
+        # If subport is set to 0, assign a default value of 1 to ensure valid subport configuration
+        if subport == 0:
             subport = 1
     else:
-        click.echo("Failed to connect to CONFIG_DB")
+        click.echo(f"{port_name}: Failed to connect to CONFIG_DB")
         sys.exit(EXIT_FAIL)
 
     state_db = SonicV2Connector(use_unix_socket_path=False, namespace=namespace)
     if state_db is not None:
         state_db.connect(state_db.STATE_DB)
-        host_lane_count = int(state_db.get(state_db.STATE_DB,
-                                           'TRANSCEIVER_INFO|{}'.format(port_name),
-                                           'host_lane_count'))
-        media_lane_count = int(state_db.get(state_db.STATE_DB,
-                                            'TRANSCEIVER_INFO|{}'.format(port_name),
-                                            'media_lane_count'))
+        try:
+            host_lane_count = int(state_db.get(state_db.STATE_DB,
+                                               f'TRANSCEIVER_INFO|{port_name}',
+                                               'host_lane_count'))
+        except TypeError:
+            click.echo(f"{port_name}: host_lane_count is not present in STATE_DB")
+            sys.exit(EXIT_FAIL)
+
+        try:
+            media_lane_count = int(state_db.get(state_db.STATE_DB,
+                                                f'TRANSCEIVER_INFO|{port_name}',
+                                                'media_lane_count'))
+        except TypeError:
+            click.echo(f"{port_name}: media_lane_count is not present in STATE_DB")
+            sys.exit(EXIT_FAIL)
     else:
-        click.echo("Failed to connect to STATE_DB")
+        click.echo(f"{port_name}: Failed to connect to STATE_DB")
         sys.exit(EXIT_FAIL)
 
     if 'host-side' in loopback_mode:
diff --git a/tests/sfputil_test.py b/tests/sfputil_test.py
index a9dd096290..3d54d5d715 100644
--- a/tests/sfputil_test.py
+++ b/tests/sfputil_test.py
@@ -1631,14 +1631,16 @@ def test_load_port_config(self, mock_is_multi_asic):
 
     @patch('sfputil.main.is_port_type_rj45', MagicMock(return_value=False))
     @patch('sfputil.main.platform_chassis')
+    @patch('sfputil.main.ConfigDBConnector')
+    @patch('sfputil.main.SonicV2Connector')
     @patch('sfputil.main.platform_sfputil', MagicMock(is_logical_port=MagicMock(return_value=1)))
     @patch('sfputil.main.logical_port_to_physical_port_index', MagicMock(return_value=1))
     @patch('sonic_py_common.multi_asic.get_front_end_namespaces', MagicMock(return_value=['']))
-    @patch('sfputil.main.ConfigDBConnector', MagicMock())
-    @patch('sfputil.main.SonicV2Connector', MagicMock())
-    def test_debug_loopback(self, mock_chassis):
+    def test_debug_loopback(self, mock_sonic_v2_connector, mock_config_db_connector, mock_chassis):
         mock_sfp = MagicMock()
         mock_api = MagicMock()
+        mock_config_db_connector.return_value = MagicMock()
+        mock_sonic_v2_connector.return_value = MagicMock()
         mock_chassis.get_sfp = MagicMock(return_value=mock_sfp)
         mock_sfp.get_presence.return_value = True
         mock_sfp.get_xcvr_api = MagicMock(return_value=mock_api)
@@ -1685,3 +1687,24 @@ def test_debug_loopback(self, mock_chassis):
         result = runner.invoke(sfputil.cli.commands['debug'].commands['loopback'],
                                ["Ethernet0", "none"])
         assert result.output == 'Ethernet0: Set none loopback\n'
+
+        mock_config_db = MagicMock()
+        mock_config_db.get.side_effect = TypeError
+        mock_config_db_connector.return_value = mock_config_db
+        result = runner.invoke(sfputil.cli.commands['debug'].commands['loopback'],
+                               ["Ethernet0", "none"])
+        assert result.output == 'Ethernet0: subport is not present in CONFIG_DB\n'
+        assert result.exit_code == EXIT_FAIL
+
+        mock_config_db_connector.return_value = None
+        result = runner.invoke(sfputil.cli.commands['debug'].commands['loopback'],
+                               ["Ethernet0", "none"])
+        assert result.output == 'Ethernet0: Failed to connect to CONFIG_DB\n'
+        assert result.exit_code == EXIT_FAIL
+
+        mock_config_db_connector.return_value = MagicMock()
+        mock_sonic_v2_connector.return_value = None
+        result = runner.invoke(sfputil.cli.commands['debug'].commands['loopback'],
+                               ["Ethernet0", "none"])
+        assert result.output == 'Ethernet0: Failed to connect to STATE_DB\n'
+        assert result.exit_code == EXIT_FAIL