When you hover over the word it says an acceptable translation is "what's up"
why was this answer not accepted?
It's probably because you didn't have "Juma" on the end. Either that, or they just hadn't made it an acceptable answer at that time. It is now, so no worries.
It also suggests "how are you" in the acceptable translations, but doesnt accept it. The correct answer suggested is "Hello, Juma" which is not one of the proposed translations.
On desktop, when you finish with a sentence you will either get the green box for a correct answer or the red box for an incorrect answer. There are two options in the bottom left of that, "Discuss Sentence" and "Report a Problem". Click the "Report a Problem", to give feedback.
I found that in Kenya, "mambo" was a very casual greeting, nearly slang. Is this correct? If so, should the user be informed?