How to distinguish reason if failed to connect

[Karl-Sparticle]

Hi,
Can u provide some advices to distinguish the reason if failed to connect.

1. network problem
2. bad username/password
3. ...

I found nothing from the error code list.

OK: {code:0, text:"AMQJSC0000I OK."},
CONNECT_TIMEOUT: {code:1, text:"AMQJSC0001E Connect timed out."},
SUBSCRIBE_TIMEOUT: {code:2, text:"AMQJS0002E Subscribe timed out."},
UNSUBSCRIBE_TIMEOUT: {code:3, text:"AMQJS0003E Unsubscribe timed out."},
PING_TIMEOUT: {code:4, text:"AMQJS0004E Ping timed out."},
INTERNAL_ERROR: {code:5, text:"AMQJS0005E Internal error. Error Message: {0}, Stack trace: {1}"},
CONNACK_RETURNCODE: {code:6, text:"AMQJS0006E Bad Connack return code:{0} {1}."},
SOCKET_ERROR: {code:7, text:"AMQJS0007E Socket error:{0}."},
SOCKET_CLOSE: {code:8, text:"AMQJS0008I Socket closed."},
MALFORMED_UTF: {code:9, text:"AMQJS0009E Malformed UTF data:{0} {1} {2}."},
UNSUPPORTED: {code:10, text:"AMQJS0010E {0} is not supported by this browser."},
INVALID_STATE: {code:11, text:"AMQJS0011E Invalid state {0}."},
INVALID_TYPE: {code:12, text:"AMQJS0012E Invalid type {0} for {1}."},
INVALID_ARGUMENT: {code:13, text:"AMQJS0013E Invalid argument {0} for {1}."},
UNSUPPORTED_OPERATION: {code:14, text:"AMQJS0014E Unsupported operation."},
INVALID_STORED_DATA: {code:15, text:"AMQJS0015E Invalid data in local storage key={0} value={1}."},
INVALID_MQTT_MESSAGE_TYPE: {code:16, text:"AMQJS0016E Invalid MQTT message type {0}."},
MALFORMED_UNICODE: {code:17, text:"AMQJS0017E Malformed Unicode string:{0} {1}."},
BUFFER_FULL: {code:18, text:"AMQJS0018E Message buffer is full, maximum buffer size: {0}."},