Error: "A slave with the same server_uuid/server_id as this slave has connected to the master"

I am testing a node.js client which connects to a mysql DB (mariadb). It works fine on its own, but if I launch this client simultaneously on another host, the first instance gets disconnected with the following error. I have read some posts suggesting to change the server-id in my.cnf, but that didn't help. Besides, why would I need to change the id of the server since both clients are pointing to the same server? { Error: UNKNOWN_CODE_PLEASE_REPORT: A slave with the same server_uuid/server_id as this slave has connected to the master; the first event 'mysql-b in.000024' at 334, the last event read from 'mysql-bin.000024' at 256, the last byte read from 'mysql-bin.000024' at 334. at Binlog.Sequence._packetToError (/home/myapp/node_modules/mysql/lib/protocol/sequences/Sequence.js:47:14) at Binlog.Sequence.ErrorPacket (/home/myapp/node_modules/mysql/lib/protocol/sequences/Sequence.js:96:17) at Protocol._parsePacket (/home/myapp/node_modules/mysql/lib/protocol/Protocol.js:278:23) at Parser.write (/home/myapp/node_modules/mysql/lib/protocol/Parser.js:76:12) at Protocol.write (/home/myapp/node_modules/mysql/lib/protocol/Protocol.js:38:16) at Socket. (/home/myappp/node_modules/mysql/lib/Connection.js:91:28) at Socket. (/home/myapp/node_modules/mysql/lib/Connection.js:502:10) at Socket.emit (events.js:182:13) at addChunk (_stream_readable.js:283:12) at readableAddChunk (_stream_readable.js:264:11) -------------------- at Protocol._enqueue (/home/myapp/node_modules/mysql/lib/protocol/Protocol.js:144:48) at Immediate._start (/home/myapp/node_modules/@rodrigogs/zongji/index.js:234:31) at processImmediate (timers.js:632:19) code: 'UNKNOWN_CODE_PLEASE_REPORT', errno: 4052, sqlMessage: "A slave with the same server_uuid/server_id as this slave has connected to the master; the first event 'mysql-bin.000024' at 334, the last event read from 'mysql-bin.000024' at 256, the last byte read from 'mysql-bin.000024' at 334.", sqlState: 'HY000' } { Error: Connection lost: The server closed the connection. at Protocol.end (/home/myapp/node_modules/mysql/lib/protocol/Protocol.js:112:13) at Socket. (/home/myapp/node_modules/mysql/lib/Connection.js:97:28) at Socket. (/home/myapp/node_modules/mysql/lib/Connection.js:502:10) at Socket.emit (events.js:187:15) at endReadableNT (_stream_readable.js:1094:12) at process.internalTickCallback (internal/process/next_tick.js:72:19) fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }