I get this message when I try to add any items in my cart on my shop. It started a while after I installed 2 apps, wich I have now deleted but the problem persists. Please, I really need help since it is absolutely blocking my shop.
These are the 2 apps :
Promotion Popup by Secomap
Discounted upsells - Cross sells & Upsells
They have good ratings so I don't know..