Issue with coupons

My coupons are not working for the membership plugin for some reason.
I have created multiple coupons in all sorts of variations with unlimited usage, no expiration for any subscription and no matter what I create, when I open a different browser to try it out (or even have someone try from a different ip address) whenever the coupon code is inserted and the person wants to subscribe with the discount it says "The coupon code is invalid or expired".
Please help