Server side validation function not blocking checkout

I’ve got the code running in my dev store and the one live store it’s for. I used the code at

For the base. Main thing I changed is the interior logic for when to report an error (set to only run on the checkout page).

It runs, it reports the error, the message shows on checkout, but it still lets you check out. I was pretty sure this worked before but now it’s not. What am I missing? I can post chunks of code if it helps but it’s pretty close to that example with only when to report an error changed and that’s working.

Well so far no luck finding a solution (sort of). I tried the example again and had the same issue, not blocking checkout. BUT I found it does work if you go to the 3 page checkout. It’s not ideal but at least functions. I was really hoping someone had a fix or at least could see if any others have found this happening (happened in our sandbox dev store and the live store)

same thing happens on our dev store, the error message pops up, but we are able to checkout

Hey folks - thanks for flagging issues with this tutorial. Digging into this on my side now.

Are your dev stores using the the Checkout and Customer Accounts Extensibility developer preview?

My dev store that I tested on, yes. It also didn’t work on what is now a live Plus store.

Looking into this more on my side now.