Why does my cart turn grey when selecting a different variant?

Hi, I am using the Refresh Theme, we have just downloaded this and started some updates.
I am trying to add variants, they are there and showing, stocks are correct, but when I click on another variant, it doesn’t update the price, and the Add To Cart blanks out, so you can’t use it.

I have trolled the internet, searching everything I can think of, and can’t find a reason as to why this is.
I can’t attach a screen shot, as it says PNG and JPEG are not supported.

Website has been down a few days already, so need to get this sorted, if anybody can help?

Also getting these messages, as can be seen in 3rd capture.
Thank you.

Did you check the inventory of those variant options in all markets and the warehouse of your store?

Hi, I did yeah, all is fine and stocked.

Could you share your store URL to check?

https://leoivyco.co.uk/products/mothers-fathers-day-postcard it is password protected you can PM me for that if you wish.

Hi, have you guys found a solution since I’m having the same issue. Thanks in advance!