PayPal payment tool is asking for "API Username". What is this and how do I proceed?

I have done this multiple times, but this time they made me set up a business account in order to use your integration.  They are now asking for a "third party API Username".  What is this and how do I proceed?

I did check your last edited form "SD16 Convention, Ads, Tables & Food Orders" and found that you have added "Paypal" payment tool which requires you to add your PayPal account email address. 

If you add "PayPal Pro" payment tool in your form, then it will ask you to add PayPal API Username, API password and API Signature. Which payment tool you want to add? 

Please take a look at the following guide for more information on PayPal and PayPal Pro:   https://www.jotform.com/help/183-Difference-Between-PayPal-and-PayPal-Pro

We will wait for your response.

I am NOT using PayPal Pro, just a business PayPal account. I was unable to interface my form with the original set up, using just a personal account, as they said it would not interface with third parties and that I had to upgrade to a business account.  In doing this it is asking for the "Third Party API User Name" in order to proceed with the upgrade.  Never had this problem with all the other forms I set up????

I checked your form, and you have integrated it with PayPal Standard.

Cloned your form and tested the Paypal Standard integration with my basic paypal account and the integration worked without any error.

May we know if the error occurs when you try to input your email in the Integration or when you are redirected to PayPal ?

You can check your PayPal API Credentials  using this guide How-to-Obtain-PayPal-API-Credentials

Here is a PayPal page that offers detailed guide on how to check your API credentials. Click Create API signature.

https://developer.paypal.com/docs/classic/api/apiCredentials/

Let us know how it goes.