It would really help if the English translations were closer to the answer you're looking for, especially in this lesson where depending on whether you're in Latin America or Spain, people could choose either option and be correct.
This is the question from the quiz that I got wrong:
Hoy no _________________ a nadie interesante.I haven't met anybody interesting today.
I selected "he conocido" because that is the direct translation and it seems like that's what they'd say in Spain due to the timing. But in Latin America (which is my selected profile but I'm not sure that it actually impacts my quizzes or not), it would be "conoci".
If you translated it to "I didn't meet anyone interesting today", that would make sense in English and prompt the correct answer, would it not? Because it seems like based on this lesson, either answer is correct depending on what Spanish-speaking country you're in!