Financial crisis is a situation where a person or organisation is unable to generate income or profits. This could happen either due to a failure of the market, a particular investment or an overall loss in the general economy of the country. Generally, a lot of people are affected at the same time and cause great distress.
Example:
For example if a company gives credit to a lot of people but is unable to get the money back, they would find it difficult to manage their assets and expenses. That would lead to a financial crisis. On a personal level, for example you lose your job and are unable to get another while your savings are slowly decreasing, that could be called a financial crisis.