"What is your name?"
Translation:Jak se jmenuješ?
Wouldn't "Jak se jmenujete?" imply that you're asking a group of people their names, which would translate to "What are your names?".
Not exclusively. "Jak se jmenujete?" is both plural and formal singular. You're asking an unknown adult individual his or her name this way.
If formal and informal levels sound silly and unnecessary to you, try to read https://news.expats.cz/czech-language/formal-informal-czech/
Většinou se otázkou "Jak se jmenujete?" ptá na jméno někoho, komu se vyká.
I went with the more literal "co je tvoje jméno" which was rejected. Now remembering this lesson is about present tense - but would the sentence be ok in general?
I'll try reporting it, just in case.