Erratic behaviour of Multi coupon extensio

-- url of the page with the problem -- : www.beeswaxcandleshop.com/store.html
-- HikaShop version -- : 4.7.0
-- Joomla version -- : 3.10.6
-- PHP version -- : 7.4.33

Problem with coupon

Hello - A few days ago I installed the multicoupon discount extension on my hikashop site.
I have been receiving erratic behaviour.
After installing the coupon, it shows on the shipping pages and works - but after a few hrs or next day it will not work - coupon text shows, but you get an error = "The coupon you entered is not valid". Last time this happened I deleted it and made a new coupon with a different code and it worked for a few days. I also noted that it could not be deleted from the checkout page using the delete button. Also, it stayed on (in chrome) and a happy customer received the discount without even entering the code.
Any ideas?

One other question - what is the the 3 empty boxes - I probably had them before but don't remember - I just upgraded to new hikashop.

www.beeswaxcandleshop.com/store/large-be...candles-pillars.html
Put something in the cart and try to check out - coupon code is MMN1776

Hello - I downloaded a new copy and installed it. When I used it, it worked, but still cannot delete it from the order form. Then I unpublished it, cleared the cache on siteground website, and it was still there. I am concerned that it wont clear by itself - I already had orders with the discount applied when it should not have. I have published it again.

Thank you - my mistake - I was re installing the coupon extension - did the whole hika file and it works now - thanks.

Bill