MQTTCLient PublishAsync() goes to WaitingForActivation

Question

I am using Mqttnet Client. When publishing Data to the mosquitto broker after few seconds the task status is WaitingForActivation.

Connect:

 var clientOptions= new MqttClientOptionsBuilder()
                            .WithProtocolVersion(MQTTnet.Formatter.MqttProtocolVersion.V500)
                            .WithClientId(ClientId)
                            .WithCredentials(BrokerUserName, BrokerPwd)
                            .WithConnectionUri(_mqttUri)
                            .WithKeepAlivePeriod(TimeSpan.FromSeconds(KeepAlivePeroid))
                            .WithTimeout(TimeSpan.FromSeconds(36000))
                            .WithMaximumPacketSize(UInt32.MaxValue)
                            .WithReceiveMaximum(ushort.MaxValue)                        
                            .WithCleanSession().Build();
  await _mqttClient1.ConnectAsync(options);

Publish:

var messageBuilder = new MqttApplicationMessageBuilder()
                        .WithTopic(publishTopic)
                        .WithPayload(payload)
                        .WithQualityOfServiceLevel(qos)
                        .WithRetainFlag(retain)
                        .Build();
 MqttClientPublishResult result= await _mqttClient1.PublishAsync(messageBuilder);

After certain publish, I don't see any messages in my Broker. When I check the Task status, its WaitingForActivation. What Am I supposed to do for continuous data publish. Any help appreciated! Thanks!