We use a modified 'Simple' theme - I dont think it's the theme causing theissue. I think it's something on the Shopify endWeirdly, it seems customers can still checkout if they are using the 'Shop'app

Hi, We received this response from Support:1:55 Tanya (Support Advisor): Hi there is an emerging incident happening which our developers are working on as fast as they can to rectify the issue. What I can do is reach out to you by email as soon as th...

If you need to, you can send customers manually to the checkout by setting up the order in draft orders and sending them the checkout link from the 'send invoice' option. (it works, we used it) Thanks

Support said its an issue that the Shopify developers are working to solve. Basically, the checkout will not load form the cart page.

Same here