Ops! Well now ya gone and done it! You thought you'd put down a few Dynamic Lighting points to spice up your map, but you sucked your players and your campaign into the eternal dark! Rest assured, we can help you guide your campaign back to the light!
Most likely what caused this issue is that you attempted to use Dynamic Lighting without first establishing bounds, or the "Dynamic Lighting Fence".
Yikes... Not very playable, unless you are trying to simulate what would happen if you put a Bag of Holding inside another Bag of Holding.
Rest assured, there is a very quick fix for this!
Dynamic Lighting can only be viewed if the token used for Dynamic Lighting is contained within Dynamic Lighting points (i.e. within the fence). To fix this, simply make a fence around your map, like so:
That should be all you need to make it work!