WE Open Bolt SCAR not firing
 

I've just installed an NPAS on my WE SCAR and now it does not fire. Not sure if it's the trigger assembly as I never touched it. Some help would be appreciated.

Some images:

http://i.imgur.com/tqe6oml.jpg

http://i.imgur.com/r8LDBNr.jpg

http://i.imgur.com/2g50ps0.jpg