Ensure the broker's URL is correct (ws://for unsecured,wss://for secured) and the port is open. For self-hosted brokers, confirm WebSocket support is enabled and accessible, considering any firewall or network
SSL/TLS might not always be an option and, in some cases, might not be desired. On such occasions, authentication is presented as a cleartext username and password, which are sent by the client to the server -- this, as part of the CONNECT/CONNACK packet sequence. In addition, some...