Are you on the quest step where you have to check all three capitals? There was a bug in the last or previous upload that the wrong quest step got marked green, so make sure you check all three locations again.
Else, what does the quest say, what you have to do right now? Remember that you can select quests to scroll down. If the text is too long, you may not see all quest steps at first, and you have to scroll down to see your current quest step.