Hi - I have another site that's started getting this generic error message, seemingly from nowhere without any changes to my site. I've read through all the other similarly-titled posts and none of those seem to have a solution that has worked for me.
I've used Chrome's DevTools to check the form data from the button - it all looks to be OK, no stray currency symbols or extraneous spaces that I can see, and as I mentioned this is code that's been working fine for years before going down over the last weekend.
I have a web app that's used a custom html subscription form for years without a hitch - it was working when I last checked it a few weeks ago.
Now, it doesn't work at all and gives me the "Things don't appear to be working" error. I literally haven't touched the code - it simply stopped working. There's no flags/problems with my account, I haven't updated any account information, I've tried sandbox, and been searching for over two hours...and finally thought I'd ask in here to see if something up or if the checkout form stuff changed.
I tried creating a new post and was told I could not.