People can not add to cart. Error. Add to cart is empty

[MariskaLab]

Hi. 

Because add to cart was not tracking anymore i contacted Orichi to check why. He told me he couldn't add products to cart. When i try at phone/mac myself it was possible to add to cart. Strange thing from 22/3 7pm no add to carts are tracked anymore till now. But after this error 21 orders were made by customers. And from today 1 order. But this is not normal we were processing 20 orders+ a day. Somethings seems off. But we have not changed anything at that moment. The only thing is that we opened a new store. I exported the theme and use this in the new store? I did some custom code for creating a different color on the add to cart. But it seems really unlikely this has anything to do with this. Does anyone knows or have an idea what is wrong here. I contact helpdesk and wait for a respons. But maybe someone can help me here????