Cafeland World Kitchen is a complex mobile game that needs internet connection to be played at all times. Even if there's a momentary cut that you may not notice, the game will stop running. This design is due to the fact that Cafeland WK needs internet connection to save your data, and without a connection your data might be lost and that's something you wouldn't want because it would mean losing your progress.
Cafeland stops running when there's no internet connection to save your progress.
Connection cuts may go unnoticable - especially while watching videos or browsing the websites because they keep working. However that doesn't always mean your internet connection is "fine". Like it is meantioned earlier your internet connection might be experiencing momentary problems and they might be going unnoticed.
That said, when the game says "No Connection" upon loading or entering, it means your internet connection is not strong or healthy enough, so please try connecting to a stronger wi-fi.
Hope this helps!