I had similar experience where it told me that a given prime number is not a prime number as it has two divisors, 1 and itself. Literally having given the reaso

I had similar experience where it told me that a given prime number is not a prime number as it has two divisors, 1 and itself. Literally having given the reason for why it should be a prime and failing to get to the correct conclusion. And it was asked in plain language.