I was playing Catan in 5120x1440 resolution for a day before it stopped allowing me to play at that resolution. I now no longer have the option for 5120x1440. I've restarted my PC... I've toggled full screen mode on and off. I can't figure out how to get my resolution back.
I found a solution on steams discussion board for this game. If you encounter the same problem as I did, go to steam select your catan universe game, right click it and find properties, then go to "Set Launch Options" and type this: -screen-width 5120 -screen-height 1440
problem solved next time you launch Catan.