Why does my mic only become 'active' when individual gain knob is turned to max?

Hey guys please help! I just purchased a Presonus AudioBox iOne and an NT1-A Rode mic. I have 2 inputs (mic and guitar) but am only using the mic input (input 1). My problem is I only receive sound from the mic when the individual gain knob on the Presonus is tued WAY up - basically to the maximum level which is all the way clockwise. Anything below this and it's as though someone just pressed the off switch. The green light stops flickering and it instantly cuts out. I'm sure this isn't meant to be how it works and there should be a gradual increase of volume as I tu the knob from left to right but this isn't the case. Any suggestions appreciated.