I built too many solar sails at once and now I'm getting the freezing/not ticking issue like athealis. It verrry slowly got better after I refreshed and more sails found their spot. Very cool concept, and I love seeing the sails cover the sun!!
I'm having this problem too. Each time I refresh it goes a few ticks, then gets stuck again. If I restart every minute or so, I get very slow progress... but if I restart too soon it loses the progress. Looks like it'll be a while before I can actually continue.
As for "too many solar sails at once," I only have one factory sending them out, though it's level 2 and it has 30k employees.