Why can't I access/unlock higher difficulties?

The expedition map can be completed not once, but four times per week! To conquer the map again, you have to unlock higher difficulties (level II, III, and IV). Click the star icon in the top left corner to open the difficulties overview:
As you can see, the default difficulty is I and it's available for free. To unlock the higher ones, a guild leader or founder has to pay goods from the guild treasury. But everyone can donate the goods to the guild treasury, only spending them is limited to leaders/founders.

The Costs of Unlocking Difficulties depend on the age and number of your guild members when the expedition begins. Each player in your guild will generate a cost based on their age. Your guild will need to pay the cumulative cost for all guild members in order to unlock the difficulty. Unlocking a difficulty makes it available to all guild members who are taking part in the current Expedition.

Related articles

• What is the Guild Expedition?
• Why can't I participate in the Guild Expedition?
• Why aren't we first place, even though we reached the 133%?
• How expensive is it to unlock difficulties?
• Will the units and goods for negotiation change, when I move up in ages?