Problem about objc_exception_throw

Today, I encounter an issue when I use UITableView's dequeueReusableCellWithIdentifier, it always throw objc_exception_throw exception.

And from the breakpoint, I can't find any clue to solve the problem.

And finally, I remember the cell is copy pasted from old cell, and I change the class of the cell.

There are some outlet for the uilabel etc.

The problem is I didn't remove it from the old referencing outlets, and add another referencing outlet.