You may experience a situation where your Alienware or XPS desktop installed with an AMD Discrete RX580 video adapter not showing anything on the external monitor. The issue occurs when connecting the external monitor using a C2G DisplayPort (DP) cable which was not supplied with the AW2518H monitor.
Using a C2G DisplayPort (DP) cable not included with the AW2518H monitor may cause the issue.
Use the original DisplayPort (DP) cable included with the AW2518H monitor to display video on the screen.