Difference between It is not a question of something and There is no question of something

it is not a question of something—is used to tell that smth. is not a factor:

• It is not a question of education. Even highly educated people are biased against females.

there is no question of something—there is no doubt about smth.:

• The coin has suffered from corrosion, yet there is no question of its antiquity or its authenticity.