Process mining can be an effective way to learn about real business processes through data, helping companies improve their operations and reach their business objectives. However, many PM projects fail and some organizations are much better at using PM than others. In this paper, we tackle the issue of understanding what can hinder process mining effectiveness in an organization through the theoretical lens of contingency theory. Contingency variables are defined as organization-specific attributes that might affect process mining results. To distinguish our work from the study of process mining critical success factors, we focus on negative contingencies for PM. We first derive an initial list of negative contingencies for process mining initiatives by running a sentiment analysis on process mining case studies. Then, we validate our findings in interviews with process mining practitioners. The interviews show a substantial agreement among practitioners on the identified negative contingencies. At the same time, they provide additional insights on how to manage the risk associated with the contingencies materialization.