PayPal Error: Things don't appear to be working at the moment.

Customers are receiving error: Things don't appear to be working at the moment. Please try again later.

This error typically occurs for two reasons:

You have entered your PayPal email address or PayPal Identity Token incorrectly. Please confirm your PayPal email address and PayPal Identity Token are entered correctly within Downloads →Settings → Payment Gateways → PayPal Standard

Your customers may also see this if Encrypted Website Payments set to ON. Setting it to OFF will resolve the issue. This setting can be adjusted from within your PayPal account by navigating to Profile → Selling Preferences → Website Payment Preferences and selecting OFF under Encrypted Website Payments