I use Roll20 with Google Chrome and am currently playing Lost mine of Phandelver having purchased the module for yourself. I think I have hit a 'wrong' button somewhere because whilst all my other floor maps are fine, Cragmaw Castle was initially OK but has now disappeared. The floor plan token at the top is still there but now has a picture of an Owlbear rather than the floor plan. I can see all the tokens and if I click on Dynamic Lighting the green lines show up. I just can't see the map.