laptop screen turns black/blank.

[thearchitectarki]

My laptop screen turns black/blank whenever I connect it to another monitor via HDMI. and the message " input not supported" appears on the external monitor. My laptop is dell i7559.

 

[ItsBatDash]

I actually had a same problem with my Raspberry Pi 3 B, so I just connected it to my TV, and then back to monitor and it worked!