How to create the coupons?

منذ ٥ أعوام

Hi, I'm new here and I'd like to create coupons but every time I try, error message appears. I tried  newstudentdiscount  with no space, it didn't work. The error message said the coupon already exists. Is something wrong with my pc settings? I've only got one student for 3 months....(´;ω;｀)