cannot add the self signed certificate to the flutter App Local Trust Certificate Store

[kira2015]

    String filePath = '/Users/xxx/mqtt.pem';
    SecurityContext security = SecurityContext.defaultContext;
    security.allowLegacyUnsafeRenegotiation = true;

    ByteData fileByte = await rootBundle.load(filePath);
    if (File(filePath).existsSync()) {
      security.setClientAuthorities(filePath);
      security.setTrustedCertificates(filePath);
      security.useCertificateChain(filePath);
    }

    _client.securityContext = security;
    _client.setProtocolV311();

log

flutter: 1-2022-08-31 11:34:31.961919 -- MqttClient::connect - keep alive is enabled with a value of 15 seconds
flutter: 1-2022-08-31 11:34:31.965749 -- MqttConnectionKeepAlive:: Initialised with a keep alive value of 15 seconds
flutter: 1-2022-08-31 11:34:31.966406 -- MqttConnectionKeepAlive:: Disconnect on no ping response is disabled
flutter: 1-2022-08-31 11:34:31.968253 -- MqttConnectionHandlerBase::connect - server test-xx.im.cn, port 19814
flutter: 1-2022-08-31 11:34:31.970540 -- SynchronousMqttServerConnectionHandler::internalConnect entered
flutter: 1-2022-08-31 11:34:31.971435 -- SynchronousMqttServerConnectionHandler::internalConnect - initiating connection try 0, auto reconnect in progress false
flutter: 1-2022-08-31 11:34:31.972216 -- SynchronousMqttServerConnectionHandler::internalConnect - insecure TCP selected
flutter: 1-2022-08-31 11:34:31.973169 -- SynchronousMqttServerConnectionHandler::internalConnect - calling connect
flutter: 1-2022-08-31 11:34:31.974252 -- MqttNormalConnection::connect - entered
flutter: 1-2022-08-31 11:34:32.012251 -- MqttServerConnection::_startListening
flutter: 1-2022-08-31 11:34:32.015683 -- SynchronousMqttServerConnectionHandler::internalConnect - connection complete
flutter: 1-2022-08-31 11:34:32.016329 -- SynchronousMqttServerConnectionHandler::internalConnect sending connect message
flutter: 1-2022-08-31 11:34:32.017215 -- MqttConnectionHandlerBase::sendMessage - MQTTMessage of type MqttMessageType.connect
Header: MessageType = MqttMessageType.connect, Duplicate = false, Retain = false, Qos = MqttQos.atMostOnce, Size = 0
Connect Variable Header: ProtocolName=MQIsdp, ProtocolVersion=3, ConnectFlags=Connect Flags: Reserved1=false, CleanStart=true, WillFlag=true, WillQos=MqttQos.atLeastOnce, WillRetain=false, PasswordFlag=true, UserNameFlag=true, KeepAlive=15
MqttConnectPayload - client identifier is : rootx
flutter: 1-2022-08-31 11:34:32.033058 -- SynchronousMqttServerConnectionHandler::internalConnect - pre sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:32.066745 -- MqttConnectionBase::_onDone - calling disconnected callback
flutter: 1-2022-08-31 11:34:37.036674 -- SynchronousMqttServerConnectionHandler::internalConnect - post sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:37.037373 -- SynchronousMqttServerConnectionHandler::internalConnect - initiating connection try 1, auto reconnect in progress false
flutter: 1-2022-08-31 11:34:37.037822 -- SynchronousMqttServerConnectionHandler::internalConnect - insecure TCP selected
flutter: 1-2022-08-31 11:34:37.038216 -- SynchronousMqttServerConnectionHandler::internalConnect - calling connect
flutter: 1-2022-08-31 11:34:37.038587 -- MqttNormalConnection::connect - entered
flutter: 1-2022-08-31 11:34:37.042051 -- MqttServerConnection::_startListening
flutter: 1-2022-08-31 11:34:37.042718 -- SynchronousMqttServerConnectionHandler::internalConnect - connection complete
flutter: 1-2022-08-31 11:34:37.043123 -- SynchronousMqttServerConnectionHandler::internalConnect sending connect message
flutter: 1-2022-08-31 11:34:37.043538 -- MqttConnectionHandlerBase::sendMessage - MQTTMessage of type MqttMessageType.connect
Header: MessageType = MqttMessageType.connect, Duplicate = false, Retain = false, Qos = MqttQos.atMostOnce, Size = 76
Connect Variable Header: ProtocolName=MQIsdp, ProtocolVersion=3, ConnectFlags=Connect Flags: Reserved1=false, CleanStart=true, WillFlag=true, WillQos=MqttQos.atLeastOnce, WillRetain=false, PasswordFlag=true, UserNameFlag=true, KeepAlive=15
MqttConnectPayload - client identifier is : rootx
flutter: 1-2022-08-31 11:34:37.044366 -- SynchronousMqttServerConnectionHandler::internalConnect - pre sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:37.108374 -- MqttConnectionBase::_onDone - calling disconnected callback
flutter: 1-2022-08-31 11:34:42.046116 -- SynchronousMqttServerConnectionHandler::internalConnect - post sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:42.046690 -- SynchronousMqttServerConnectionHandler::internalConnect - initiating connection try 2, auto reconnect in progress false
flutter: 1-2022-08-31 11:34:42.047108 -- SynchronousMqttServerConnectionHandler::internalConnect - insecure TCP selected
flutter: 1-2022-08-31 11:34:42.047486 -- SynchronousMqttServerConnectionHandler::internalConnect - calling connect
flutter: 1-2022-08-31 11:34:42.047864 -- MqttNormalConnection::connect - entered
flutter: 1-2022-08-31 11:34:42.055768 -- MqttServerConnection::_startListening
flutter: 1-2022-08-31 11:34:42.056356 -- SynchronousMqttServerConnectionHandler::internalConnect - connection complete
flutter: 1-2022-08-31 11:34:42.056759 -- SynchronousMqttServerConnectionHandler::internalConnect sending connect message
flutter: 1-2022-08-31 11:34:42.057141 -- MqttConnectionHandlerBase::sendMessage - MQTTMessage of type MqttMessageType.connect
Header: MessageType = MqttMessageType.connect, Duplicate = false, Retain = false, Qos = MqttQos.atMostOnce, Size = 76
Connect Variable Header: ProtocolName=MQIsdp, ProtocolVersion=3, ConnectFlags=Connect Flags: Reserved1=false, CleanStart=true, WillFlag=true, WillQos=MqttQos.atLeastOnce, WillRetain=false, PasswordFlag=true, UserNameFlag=true, KeepAlive=15
MqttConnectPayload - client identifier is : rootx
flutter: 1-2022-08-31 11:34:42.057953 -- SynchronousMqttServerConnectionHandler::internalConnect - pre sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:42.116857 -- MqttConnectionBase::_onDone - calling disconnected callback
flutter: 1-2022-08-31 11:34:46.969717 -- MqttConnectionKeepAlive::pingRequired - NOT sending ping - not connected
flutter: 1-2022-08-31 11:34:46.970246 -- MqttConnectionKeepAlive::pingRequired - restarting ping timer
flutter: 1-2022-08-31 11:34:47.061118 -- SynchronousMqttServerConnectionHandler::internalConnect - post sleep, state = Connection status is connecting with return code of noneSpecified and a disconnection origin of none
flutter: 1-2022-08-31 11:34:47.061650 -- SynchronousMqttServerConnectionHandler::internalConnect failed
flutter: MQTTX 连接报错:mqtt-client::NoConnectionException: The maximum allowed connection attempts ({3}) were exceeded. The broker is not responding to the connection request message (Missing Connection Acknowledgement?
flutter: MQTTX 连接失败

My demo can be connected to broker.emqx.io:1883 without using a certificate

[shamblett]

You are connecting and sending a connect message which is being rejected by your broker, you need to check your broker logs to find out why.

The SecurityContext class is provided by the Dart/flutter runtime here , not the client. If you are having problems with this or your platform you need to contact the flutter guys at Google, the client can't help you with this.