Answer:
Martin Luther disagreed over many things with the Catholic Church. However, his main disagreement was over the payment of indulgences.
Step-by-step explanation:
Indulgences were payments that people could make to the Catholic Church in exchange for having their sins forgiven. This system came to be abused by wealthy and powerful people of the time, and Martin Luther felt that this was a deeply corrupt practice.
This is why in his 95 theses, he publicly denounced the practice of indulgences, a denounce that led to his excommunication from the church.