Were abouts does the drain hose from the washer go?
Is it going to a spout under the sink?
Its got its own drain outlet but is connected to the sink externally.
Ok if its going into its own stand pipe then its the drains at fault here.
Might be worth remove the U bend pipe under the sink and check for any blockages in there.
Or pore drain cleaner down the pipe were the waste hose goes and hopefully this will clear it.
As if the fault was on the old washer and its the same with the new washer then the smell is coming up from the drains. So use a drain cleaner and pore it down the sink and into the stand pipe and this should cure the problem and stop the smell from backing up into the washer.
ok will give this a go
No worries that should sort it out.