Modbus read in two differents unitId

hello everyone and thank you in advance to those who will read my question.
sorry for my level of English but I'm a little French.
i have sone troubles with modbus serial

in node-red.
i can read separatly in two different unitid when there is one flex-getter set to disable. when i activate both of them, i lose connection. i've tried to use flex-connector but i don't how to use it. can any one tell me how to do that or give me an other solution?

thank you in advance!