Here are the most common reasons
You applied only to programs in which you had zero chance of gaining admission
You bombed the in-person/phone interview
You didn’t meet the specific math/programming/finance/experience requirements
You failed to make a compelling case for why you need the MFE degree
Your GRE/GMAT/GPA/TOEFL scores are too low compared to the overall applicant pool
You failed to customize your applications to each program you applied to
You disclosed your plan of doing PhD after MFE
Your essay showed lack of English proficiency or was written by someone else
You failed to proofread and named a different program in your essay
You failed to address specific questions asked in the essay topic
Your application had fundamental flags around judgment or interpersonal issues.
You failed to present new information when you reapplied
Your recommendations had a damning effect
You rushed the application and didn’t spend enough time on it
You failed to complete the application or provide missing documentation