Error: CONF_DONE pin failed to go high in device 1

[Altera_Forum]

while downloading my program 'sof', am getting 

 Error: CONF_DONE pin failed to go high in device 1  what could be the possible problems?

[Altera_Forum]

Did you try other SOFs? 

Is there a pull up on the CONF_DONE pin and is it connected properly?

[Altera_Forum]

yes. I tried with other sofs also, but the problem was same. 

yesterday what i did was, that i changed my blaster, and found that it configured properly, without giving error (in some threads on forum also same solution was discussed).  but today, with new blaster also same error is coming. i went for third one, but error persisted.

[Altera_Forum]

You could check the JTAG signals with an oscilloscope. It is strange that nothing is detected by the JTAG probe during configuration though...

[Altera_Forum]

check if the pin assignments contain a switch that must be high or a press key and  

make sure you are not using a time_limited sof file