Coupon does not exist

Hello everyone

I created a coupon called “xxx” using Woocommerce. However, when I applied it, it’s said, “Coupon “xxx” does not exist.” Both in cart and checkout page.

Fact:
1. I have enabled the use of a coupon in the setting page.
2. I have tried in a different browser, without logging in.
3. My first coupon worked well, and I followed the instruction.

Could you please help me?

Any answer will be much appreciated.

Thank you,
Alv

https://wordpress.org/plugins/woocommerce/