Keil Download Program Error


I got a discovery kit .(stm32l discovery kit) when i try to load some basic 

blinky code to my processor -  after the compiling -  I got some error mesage ; 

"No target connected " and "Error : Flash download failed target dll has been canceled "

 after this message i did some actions for solving this problem (for example ;

I did ; Utilities --> Debug ---> Connect ---> Choose ,Reset after Connect) but

Nothing solved.

I am demanding your valuable suggestions...

More questions in this forum