Modbus cannot connect to slave in OH3

Just migrated to OH3, having problems with modbus tcp.

2021-05-12 23:19:26.336 [ERROR] [ing.ModbusSlaveConnectionFactoryImpl] - Error connecting connection TCPMasterConnection@24497d9e[socket=Socket[unconnected]] for endpoint ModbusTCPSlaveEndpoint@46fb304d[address=192.168.1.50,port=504]: В соединении отказано (Connection refused)
2021-05-12 23:19:26.336 [WARN ] [rt.modbus.internal.ModbusManagerImpl] - Could not connect to endpoint ModbusTCPSlaveEndpoint@46fb304d[address=192.168.1.50,port=504] – aborting request ModbusReadRequestBlueprint@7538a68e[slaveId=42,functionCode=READ_COILS,start=1,length=2,maxTries=3] [operation ID f202ab3f-36cd-4e82-9338-a5875e07c395]
2021-05-12 23:19:26.337 [DEBUG] [bus.handler.ModbusPollerThingHandler] - Thing modbus:poller:7c7ecf34a5:f6e2db4137 received response PollResult(failure=AsyncModbusReadResult(request = ModbusReadRequestBlueprint@7538a68e[slaveId=42,functionCode=READ_COILS,start=1,length=2,maxTries=3], error = ModbusConnectionException(Error connecting to endpoint=ModbusTCPSlaveEndpoint@46fb304d[address=192.168.1.50,port=504])))

Although other tools like ModbusPoll works fine with the same slave

Tx:000024-0B 69 00 00 00 06 2A 01 00 00 00 02
Rx:000025-0B 69 00 00 00 04 2A 01 01 00
Tx:000026-0B 6A 00 00 00 06 2A 01 00 00 00 02
Rx:000027-0B 6A 00 00 00 04 2A 01 01 00
Tx:000028-0B 6B 00 00 00 06 2A 01 00 00 00 02
Rx:000029-0B 6B 00 00 00 04 2A 01 01 00
Tx:000030-0B 6C 00 00 00 06 2A 01 00 00 00 02
Rx:000031-0B 6C 00 00 00 04 2A 01 01 00
Tx:000032-0B 6D 00 00 00 06 2A 01 00 00 00 02
Rx:000033-0B 6D 00 00 00 04 2A 01 01 00
Tx:000034-0B 6E 00 00 00 06 2A 01 00 00 00 02
Rx:000035-0B 6E 00 00 00 04 2A 01 01 00
Tx:000036-0B 6F 00 00 00 06 2A 01 00 00 00 02
Rx:000037-0B 6F 00 00 00 04 2A 01 01 00

Any help appreciated. Thanks in advance

Your target device says “no”. That may be because it has too many connections already.

From the packet sniffer I can see there is only single host connected
image

Actually it was reconnectAfterMillis parameter - is it possible to disable these auto-disconnects at all?