Trouble drilling into outside facing wall above window to hang curtain rod
Sometimes when drilling above a window, a lintel is encountered, which may be made of concrete, reinforced concrete, or steel. It may be necessary to move the curtain rod higher so that the  center support mounting can be installed above the lintel. If that is not an option due to curtain length, an "L" bracket can be used to extend the mounting of the support higher. Downside: the bracket will be visible whether the curtains are open or closed. Camouflage with paint if not a aesthetically pleasing.