diff --git a/package/cloudshell/cm/customscript/domain/linux_script_executor.py b/package/cloudshell/cm/customscript/domain/linux_script_executor.py
index d26ef52..c6311c2 100644
--- a/package/cloudshell/cm/customscript/domain/linux_script_executor.py
+++ b/package/cloudshell/cm/customscript/domain/linux_script_executor.py
@@ -47,8 +47,10 @@ def connect(self):
                 key_stream = StringIO(self.target_host.access_key)
                 key_obj = RSAKey.from_private_key(key_stream)
                 self.session.connect(self.target_host.ip, username=self.target_host.username, pkey=key_obj)
-            else:
+            elif self.target_host.username:
                 raise Exception('Both password and access key are empty.')
+            else:
+                raise Exception('Machine credentials are empty.')
         except NoValidConnectionsError as e:
             error_code = next(e.errors.itervalues(), type('e', (object,), {'errno': 0})).errno
             raise ExcutorConnectionError(error_code, e)
diff --git a/package/tests/test_linux_script_executor.py b/package/tests/test_linux_script_executor.py
index 4014a93..454f7ad 100644
--- a/package/tests/test_linux_script_executor.py
+++ b/package/tests/test_linux_script_executor.py
@@ -64,6 +64,12 @@ def test_no_password_nor_pen_file(self):
             executor.connect()
         self.assertEqual('Both password and access key are empty.', e.exception.inner_error.message)
 
+    def test_no_password_no_pen_file_no_username(self):
+        executor = LinuxScriptExecutor(self.logger, self.host, self.cancel_sampler)
+        with self.assertRaises(Exception) as e:
+            executor.connect()
+        self.assertEqual('Machine credentials are empty.', e.exception.inner_error.message)
+
     def test_create_temp_folder_success(self):
         self._mock_session_answer(0,'tmp123','')
         result = self.executor.create_temp_folder()