A: You lost focus And Lost Effect
B: You Have Not Trained Your Self Long Enough(practice, dose more)
C: It May Have Been You Got To Exited And Lost Control OF your Concentration
This is what i think you should do, Try it again tomorrow or LATER,
and keep focus the whole time, then take the headphones off and Enjoy,
or if you must do it soon, do the reset, or Brain + or Condition dose, don't have it, then you should wait a bit