diff --git a/pymanager/manager.py b/pymanager/manager.py
index 1960f53..093fbba 100755
--- a/pymanager/manager.py
+++ b/pymanager/manager.py
@@ -142,6 +142,7 @@ import json
 import fcntl
 import os
 import base64
+from socketserver import ThreadingMixIn
 
 try:
     import bcrypt
@@ -455,7 +456,7 @@ class ManageHttpRequest(http.server.SimpleHTTPRequestHandler):
         self.end_headers()
 
 
-class khaganatHTTPServer(http.server.HTTPServer):
+class khaganatHTTPServer(ThreadingMixIn, http.server.HTTPServer):
     """
         Class khaganatHTTPServer
         Redefine HTTPServer (adding queue input & queue output, use by ManageHttpRequest)
@@ -669,38 +670,50 @@ class ManageCommand():
         if not self.process:
             return "stopped"
         else:
-            code = self.process.poll()
-            loop = self.maxWaitEnd
-            while (code is None) and (loop > 0):
-                logging.debug("stop process %s", self.name)
-                self.process.send_signal(15)
-                time.sleep(1)
+            try:
                 code = self.process.poll()
-                loop -= 1
+                loop = self.maxWaitEnd
+                while (code is None) and (loop > 0):
+                    logging.debug("stop process %s", self.name)
+                    self.process.send_signal(15)
+                    time.sleep(1)
+                    code = self.process.poll()
+                    loop -= 1
+            except ProcessLookupError as e:
+                logging.warning("Stop process (%s)" % str(e))
 
-            loop = self.maxWaitEnd
-            while (code is None) and (loop > 0):
-                logging.debug("terminate process %s", self.name)
-                self.process.terminate()
-                time.sleep(1)
-                code = self.process.poll()
-                loop -= 1
+            try:
+                loop = self.maxWaitEnd
+                while (code is None) and (loop > 0):
+                    logging.debug("terminate process %s", self.name)
+                    self.process.terminate()
+                    time.sleep(1)
+                    code = self.process.poll()
+                    loop -= 1
+            except ProcessLookupError as e:
+                logging.warning("Stop process (%s)" % str(e))
 
-            loop = self.maxWaitEnd
-            while (code is None) and (loop > 0):
-                logging.debug("kill process %s", self.name)
-                self.process.send_signal(9)
-                time.sleep(1)
-                code = self.process.poll()
-                loop -= 1
+            try:
+                loop = self.maxWaitEnd
+                while (code is None) and (loop > 0):
+                    logging.debug("kill process %s", self.name)
+                    self.process.send_signal(9)
+                    time.sleep(1)
+                    code = self.process.poll()
+                    loop -= 1
+            except ProcessLookupError as e:
+                logging.warning("Stop process (%s)" % str(e))
 
-            code = self.process.wait()
-            self.process = None
-            if self.threadRead:
-                self.eventRunning.clear()
-                self.threadRead.join()
-                self.threadRead = None
-            logging.info("%s stopped (return code:%d)" % (self.name, code))
+            try:
+                code = self.process.wait()
+                self.process = None
+                if self.threadRead:
+                    self.eventRunning.clear()
+                    self.threadRead.join()
+                    self.threadRead = None
+                logging.info("%s stopped (return code:%d)" % (self.name, code))
+            except ProcessLookupError as e:
+                logging.warning("Stop process (%s)" % str(e))
             return "stopped"
 
     def getlog(self, firstline):
diff --git a/tests/test_manager.py b/tests/test_manager.py
index 5502b5a..f362a50 100644
--- a/tests/test_manager.py
+++ b/tests/test_manager.py
@@ -339,7 +339,7 @@ class TestManager(unittest.TestCase):
             self.assertEqual(res, 'stopped')
             self.assertTrue(True)
         except Exception as e:
-            self.fail('Error when run test',  e)
+            self.fail('Error when run test (%s)' % str(e))
 
     def test_execute_command_crashed(self):
         try: