The scene is empty with just a Chair[A Static Mesh Component].
Tried cleaning the project.
I am completely new.
This is a known issue in 4.20 and 4.20.1 which has been reported and has been declared fixed but they haven't patched it in the engine yet.
It is only an intellisense error however. If you have problems compiling then just use the in - editor button for compilation and don't compile from Visual Studio.
Here is the original bug report: https://issues.unrealengine.com/issue/UE-62042
The fix will be included in 4.20.2 when it releases.