Can't step into engine code

installed debugging symbols and source code.

And I put a breakpoint on this code and can’t step into the engine code.

FVector NewLocation = UKismetMathLibrary::VInterpTo(A, B, DeltaTime, MoveSpeed);

Installing source code and symbol is not enough to debug?

Should I download source code from github and build debug configuraton?

Assuming you are using Visual Studio, then could it just be that you don’t have it configured to a debug build?

yes. visual studio 2017, debug build.