Disconnected wire unit between the “CTRL IN” and “CTRL OUT” sockets of the LPS units.

Reconnect the wire unit between the “CTRL IN” and “CTRL OUT” sockets of the LPS units.

Malfunction of one of the LPS units. The orange LED (Heartbeat) of the malfunction LPS is not blinking.

Replace the whole LPS module. See "Removal of an LPS module".