MQTT Server has frequent problems with clients can't eastablish connection completely

[952795]

I'm using the MQTTnet with V4.3.3.952. There 're some problems when I testing. Testing steps are as follows:

• a MQTT Server, a Managed MqttClient, a MQTTX Client
• When the Server and managedClient execute several minites, the managedClient will hang.
• At the same time, When I use the MQTTX Client connect to the server, the server will finish the executation of the valitation and return the "Success" reasoncode, but the client still at the state of connecting, it can't establish the connection completely.
• When I create other clients to try to connect, the result is the same