Learning SASS from freecodecamp is becoming a very tedious

Although I am not making any mistake in many of questions as i have clarified in forums as well ,still the test cases in majority of the problems are not getting passed .Is this problem occuring with others also?

Are you by any chance using Edge, IE, or Safari as your browser? These have decided not to implement new features of JS and CSS according to web standards and as a result they often exhibit unintended (and frustrating) behavior.