What is ironic about Dimmesdale’s incredible success as a minister?

Dimmesdale was so spiritually wounded to begin with. Dimmesdale suffered from a spiritual crises inside himself. He felt the deep lashes of guilt and culpability for his own sins. I think Dimmesdale took his inner crisis and used it to project onto his sermons. He felt that by preaching against sin, he felt a sense of momentary absolution.