Hi,

Could you please provide us with some additional information about your setup?
Which target device device do you use? Is it mounted on an evaluation board or custom hardware?
Optional: Could you provide a link to the documentation of the board and / or the device?

Which IDE / Debugger do you use?

(The following information is conveniently output by J-Link Commander on startup:)
Which J-Link do you use?
Which version of the J-Link software & documentation pack do you use?

In order to narrow down the list of possible causes of this issue:
Could you please give J-Link Commander a try?
J-Link commander is part of the J-Link software package, which is available free of charge here .

• Start J-Link Commander (jlink.exe)
• Type "connect" in order to start a debug session
• Type in the target device name if asked (Or type "?" for a target selection Dialog)
  
• Choose the correct target interface (JTAG/SWD/etc..)
  
• Use a valid speed (Default: 4000kHz, try 100-500 if default does not work)
  
• [JTAG only]JTAG conf can be default(most of the times)
  
• You should now be successfully connected.
• It is now possible to program a binary file via the >loadfile< command
• The commands >r<, >g<, >h<, >s< can be used for reset, go, halt and step.
• Breakpoints can be set by using the >setbp< command.

If anything fails, could you please post a screenshot of the complete session?

Best regards,
Niklas