Paypal express error

A pop up says there is a

[Paypal express error]

An error has occurred. Please contact administrator for assistance. (transaction refused because of an invalid argument. See additional error message for details.)

-You are not signed up to accept payment for digitally delivered goods. 

Is this in Paypal or Jot Forms? and Help!

That's something that comes from your PayPal account. Make sure that you have enabled PayPal express in your Paypal account, you may check this guide: http://www.jotform.com/help/285-Configuring-PayPal-Express-Integration 

Also, it could be that the information you provided in the Payment configuration is not correct, please make sure to input the correct API details, also review this guide: http://www.jotform.com/help/284-How-to-Obtain-PayPal-API-Credentials 

Let us know if that helps.