Strange occurance with Nmodbus

[Talisman]

4 devices, all the exact same.

The only difference is each has its own IP and unique modbus ID.

Nmodbus sees the device with address 1 but none of the others.

Tried a second set of 4 like devices, nmodbus only sees the one with
address 1.

I am new to Nmodbus so not sure what I am missing. The other devices
have address of 2,3 and 4.

Thanks