Hi, sorry you are having some trouble. Double-check that the batteries are inserted the correct way, and are fully charged (one full day in bright sun). Also, the dawn-to-dusk sensors on the lanterns are light-sensitive, so if they are placed too close to each other, light from the larger one may interfere with the smaller lantern's sensor. Please see the user manual for more details on troubleshooting. The manual can be found under the Product Specifications tab (below the images).