Paypal integration error: Data does not match input character set

I have a SALE page I update about once a week, and I've been using it for over 3 years. On my most recent update, my users are getting this error when they try to proceed to checkout: Data does not match input character set or default encoding. For more information, please contact the merchant.

I didn't do anything. Why isn't my form integrating with Paypal?

my form is at http://www.redpennyprinting.com/sale.html

Hi,

I checked your website and noticed that you are using the Javascript embed method. Some of your website scripts might conflict with the Jotform script. Can you try re-embedding your form using the iFrame embed method and see if it solved the issue? The iFrame embed method guide can be found here: Getting the Form iFrame Code.

Do let us know if it didn't resolve your problem.

Regards.