The storefront version I'm using is -
AspDotNetStorefront Multistore 9.3.0.0/9.3.0.0
which I have upgraded from an older ML 8 version.
After upgrading the database, there are two relevant tables -
i) Coupon
ii) Promotions
All previous coupon code exist in both the table.
Now, if I add a new code from admin --> Configuration --> Pricing and Promotions --> coupons, I checked that that new code only saved in Promotions table.
If I used this code in front-end and click on Update cart button it shows the description like "Free Shipping" or "5% Discount" but after that if I click on "checkout now" button I'm getting an error message like -
"YOU HAVE ENTERED AN INVALID COUPON CODE"
If I use any old coupon-code (one that is available in both the Coupon and Promotions table in the database) then it works fine.
I have also checked at the back-end and the expiration date of the coupon is lot longer than current date and there are lots of available usage.
Not sure why this is happening. Any ideas/feedback on this will be really appreciated.