First time with this error - Inconsistent accessibility

Question

This is my first time working with interfaces and proper namespace structure. When I compile I get the error below, I have no idea what it means. Any searches I do shows up

Answer 1

IOperatorRequest is internal which is less accessible than public.

Top-level types, which are not nested in other types, can only have internal or public accessibility. The default accessibility for these types is internal.

from MSDN