Hey @Rad,
I was just checking in as you said that the checkout page has no internal error anymore but for some reason the entire website has an Internal Error now
Are you sure you are on the correct website ? I believe Christian once also thought the issue was solved however, he was also just on the wrong website. The website with the issue is stiickzz.pro not stiickzz.com
Also, since I didnāt touch the website since my last post 2 days ago, where the site was still working completely fine except for the checkout page) I assume one of you guys changed some stuff in the server files which causes the internal error throughout the whole site.