Hi Jana,

The anonymous user has no access rights to the entity under that button or no access to the microflow under that button. And maybe because you use an association between the cart and the user/account. As the anonymous user has no account, this would not work for anonymous. You can put the data of the cart in a cookie (with the risk that Chrome is deprecating the cookies later), or you store the cart with reference to the session ID (This will have some downsides as well as the session ID will be lost when closing the browser).  For the button's you can have 2 buttons each with the visibility conditions set (anonymous and not anonymous). I hope this helps. If not, we should do a share screen session.