Coupon Code Not Working

[Poshak]

Hello - this is a long standing issue and I have tried sorting it out with Support, but haven't had any luck.  Ever since Coupons have moved under Square Marketing, its been a challenge to set them up, becuase no matter what I try, they do not seem to work.  

I have tried 10% coupon that was apply to Entire Site.  I have activated the coupon, but when I try to enter it on my website, the coupon is not captured at all.  Used to be very simple, but not anymore.  

Can anyone help?