Why did I get result code -99?

Below are the causes and solutions to this error:

Your computer has insufficient memory, or the application is using up all available memory. Restart your computer or the application.
The transaction was sent to manager.paypal.com. This endpoint doesn’t process transactions; it’s the PayPal Manager website. Modify the URL within your application, website, or parameter string to point to either of the following endpoints:
- Test: pilot-payflowpro.paypal.com
- Live: payflowpro.paypal.com