220 mailpot.garrows.com SMTP Server {"id": 1, "method": "mining.subscribe", "params": ["MinerName/1.0.0", "EthereumStratum/1.0.0"]} 500 Syntax error [{"id": 1, "method": "mining.subscribe", "params": ["MinerName/1.0.0", "EthereumStratum/1.0.0"]}]