why did yahoo answers delete my question?

If by the end of the voting period the majority of the users voted <no best answer>, the question will have gotten deleted.

There are 2 possibilities. The question finished voting & the best answer was reported as a violation, which would also cause the removal of the question since it was at point a resolved question. & if you did not get a violation notice in your inbox or spam folder then that is most likely the case.

Or if you did a notice in either of those places that you have not noticed yet, then it was your question that was reported & removed.

I am not sure if a question is sent to the team for review in an email & they remove it , if a violation notice is given or not or if they just remove it. So if you do not have a notice that may also be a possibility*

if you posted what the question was in the additioal details we would be more able to answer your question