Question Cannot duplicate display but can extend . How to fix?

[DRM360]

I cannot duplicate my screen while i can only extend the screen.
When i duplicate the screen the external displays shows input not supported and i have change the resolution to the native resolution of the external display but it has not been fixed. Any solution please ? Please someone help me thanks in advanced.

 

[rgd1101]

what are the 2 screen resolution and refresh rate? better yet, tell us the exact model