The church always told people right from wrong. So when the plague hit, people assumed they had done too much wrong and that it was god's punishment to them. Therefore, they turned to the church for help to teach them how to do things the 'right' way. This meant the church was a lot busier than usual therefore they had a lot more pressure on them. After people realized that even with the help of the church, everyone was still dying, the church's reputation went down, as they were of no help, therefore not godly.