When I connect to IBM MQ QueueManager using multi-threading, it does not connect all of the requests to MQ. Few connect and few fail. If I use thread count as 1 then all the request are connected. When I increase thread count to 2 or 3 then few will success and few will fail.

Iam using below code in C#.

public string PutMessageOnQueue_Inward(string message, string strMessageID)
        {
            string writeQueueName = Common.WRITE_MESSAGE_QUEUENAME_INWARD;
            try
            {
                Hashtable properties = new Hashtable();

                properties.Add(MQC.TRANSPORT_PROPERTY, MQC.TRANSPORT_MQSERIES_MANAGED);
                properties.Add(MQC.HOST_NAME_PROPERTY, Common.FTS_MQ_HostName);
                properties.Add(MQC.CHANNEL_PROPERTY, Common.QUEUE_CHANNEL);
                properties.Add(MQC.PORT_PROPERTY, Common.FTS_MQ_Port);
                properties.Add(MQC.USER_ID_PROPERTY, Common.FTS_MQ_UserId);
                properties.Add(MQC.PASSWORD_PROPERTY, Common.FTS_MQ_Password);
                properties.Add(MQC.USE_MQCSP_AUTHENTICATION_PROPERTY, true);

                using (var objMQQueueManager = new MQQueueManager(Common.QUEUEMANAGER_NAME, properties))
                {
                    using (var objMQQueue = objMQQueueManager.AccessQueue(writeQueueName, MQC.MQOO_OUTPUT + MQC.MQOO_FAIL_IF_QUIESCING))
                    {
                        var objPutMQMessage = new MQMessage
                        {
                            //UTF-8 character encoding 
                            CharacterSet = 1208,
                            Format = MQC.MQFMT_STRING,
                            MessageType = MQC.MQMT_DATAGRAM,
                            Report = MQC.MQRO_NONE,                            
                        };

                        objPutMQMessage.WriteString(message);

                        objMQQueue.Put(objPutMQMessage);

                        objMQQueueManager.Commit();
                        objMQQueue.Close();
                        objMQQueueManager.Disconnect();                                            
                    }                    
                } 
            }
            catch (MQException mqEx)
            {
                message = null;
            }
            catch (Exception ex)
            {
                message = null;
            }

            return message;
        }