Shop data not transferred correctly in Express Checkout live API

[engelstein]

I am using NVP/SOAP API for Express Checkout on my Laravel site. It is working fine.

Now I am about to rebuild the website. I've slightly changed some of the logic in the checkout process, but in general I've used all methods in my PaypalController as they're being used on the current site.

Now with our Sandbox account, everything is working perfectly fine. I've tested it several times both, on my local machine as well as on a subdomain of our current site. 

As soon as I try to test the live API, the shop data don't seem to be transferred correctly to PayPal. The redirect is working, but when I login into my (private) PayPal Account to confirm the payment, my address data are not shown in PayPal. Thus, also the redirect to our shop fails as I go on further.

I have checked all methods in my PayPal API and I also compared them to the methods of the PayPal API of our current site. But I can't find what's wrong with it, especially as it is working in sandbox mode. Here are some screenshots of my code:

expressCheckoutgetCart => $items comes from a Trait where shop Items are being definedsetCartItemssetExpressCheckout

Is there anyone who has an idea what is going wrong here? Any help appreciated...