With 'may' there is a stronger possibility of an event occurring than with 'might'. So, with "It may make sense" there is a strong chance of it making sense, but it is not certain. With "It might make sense" the chance of of making sense is less than when you use 'may'. 'Maybe' means 'perhaps' here. "Perhaps/maybe it makes sense.

May = a possibility. Might = the past of may, so a sentence with might would have to be written in the past and the tenses must match Maybe = a possibility May and maybe when used as a suggestion can sometimes have very subtle differences. might and may are often used interchangeably by speakers which ignores the past tense definition of "might" it seems to be that language is changing and all three are now becoming merged to mean the same in all situations.