1. Insufficient level: In the game, we have a meeting at level 4 to start the transaction function. If both sides of the transaction are above level 4, then the transaction can be made. If one side of the transaction is below level 4, then we can't trade.

2. Shortage of ingots: In the game, both parties need to spend 1 ingots as a handling fee for each transaction, so the transaction will fail if the ingots of both parties are less than 1.