If you test your Paypal Business integration with the same or another Business account there might be a problem. Paypal forbids payments between two Business accounts.
Check your Paypal payment URL. If you pay on the «sandbox.paypal.com» then your account is in Sandbox mode. It can be tested with Sandbox accounts only.
There is a Paypal article how to create sandbox accounts — https://developer.paypal.com/docs/classic/lifecycl...
If you see «code=EWP_SETTINGS» in the URL of your Paypal error, you need to allow unencrypted websites to make payments to Paypal. In order to do so, login to your PayPal account then: Profile & Settings → My Selling Tools → Website Preferences
Go down to the section "Encrypted Website Payments" and select "off" to the "Block Non-encrypted Website Payment:"