I am not sure if this is a bug or whether the problem is in my own understanding, so that is why I am asking here. In the fifth mission of the Hautevilles, building a Wonder is a main objective to win the game. However, I cannot build one. The following image illustrates the problem.
It says a Wonder costs 1000 of every resource except Food, and I have all these resources. Also, the hints and objectives say nothing about needing to do something to unlock the Wonder.
So is this a bug or…?