@mprough and @jewelm,

You can do some basic debugging by editing line 11 of the square_handler.php and setting false to true.


@jewelm, Are you sure you brought the square.handler.php file over from test to production? Square needs to be told the correct URL and of course the file needs to exist.
What happens when you go to https://your_site.com/square_handler.php ? (yes, HTTPS) Normally you want to just see a white page. But if you're getting an error (ie: 404-not-found, etc) then you'll need to fix that, cuz Square will also see the error and thus will fail.

After setting $verbose=true like I mentioned above, visiting the square_handler.php with your browser should give you some text about the current token status according to your store. You can use that for troubleshooting.