Sound and light won't operate in the monitor mode anymore.

We have 2 of the sound and light machines one for each child. For some reason the second one decided to stop doing the monitor function. The first one still works fine.

Kid one has a camera and sound/light machine in the room. Kid 2 has a camera in the nursery but the sound machine is in the master bedroom because we haven't transitioned into the nursery yet. All on the same network plenty of bandwidth everywhere in the house. No change as far as I can gather.