Muzzle Flash Not Working

Hello everyone

I'm having an issue with the muzzle flash in the first person shooter tutorial, the flash does not occur when I press the left mouse button. I've put the muzzle flash from the machine gun prefab into the machine gun script. The picture I have attached if of where I have placed everything.

The muzzle flash appears in the scene and game view but when I play it no longer appears.

Please let me know if there is any fix!

If you need more info please let me now :)

Thanks for any help.