Cant place an order in vsf

Hi,

Setup

I set up the production setup of Vue Storefront. I installed https://github.com/DivanteLtd/vue-storefront/tree/release/v1.11 and https://github.com/DivanteLtd/vue-storefront-api/tree/release/v1.11-rc1

I followed the documentation for the installation of all the requirements and dependencies (nginx, redis, elasticsearch, node, yarn, …).

I used yarn, yarn build and yarn start and all works fine.

Problem

When placing an order, the order fails. I get the error message

Cannot read property ‘toString’ of undefined
at a.prepareOrder (Checkout.js:265)
at a.placeOrder (Checkout.js:312)
at a.onDoPlaceOrder (Checkout.js:167)
at Ht (vue.runtime.esm.js:1854)
at $n.t.$emit (vue.runtime.esm.js:3882)
at $n. (index.ts:12)
at Ht (vue.runtime.esm.js:1854)
at $n.t.$emit (vue.runtime.esm.js:3882)
at a.placeOrder (OrderReview.ts:33)
at click (OrderReview.vue?9f8a:4)

I already red [Magento 2.3 with Vue Storefront: Error placing an order: Cart_id should be a string (but is integer)], but it doesn’t fix the problem. Does any have some ideas how to fix it?