There are several reasons why Happiness Wuqing Coupon can't be used:

1. Coupon has expired.

2. The goods purchased are not within the scope of use of the coupons.

3. The user's equipment may have other mutually exclusive benefits, and some merchants specify that they cannot enjoy more than two benefits.

4. Before using coupons, you should carefully observe the rules for using coupons and use them according to the rules.