Errors faced during PayPal Setup

If your PayPal account is NOT able to authenticate during test transaction:

"PayPal was unable to authenticate your account. Please verify that the credentials you have entered are accurate or re-enter your credentials by copying and pasting from your PayPal account screen. If this problem persists, please contact PayPal for assistance as there is likely a problem with your PayPal merchant account. Although we would like to be of greater assistance, unfortunately, we are unable to contact PayPal on your behalf because we do not have direct access to your PayPal account."

If your Paypal account is able to authenticate during test transaction but the payment cannot be completed:

"PayPal was unable to complete the transaction. Please try using a different credit card or accepted PayPal form of payment. If this problem persists, please contact PayPal for assistance as there is likely a problem with your PayPal merchant account. Although we would like to be of greater assistance, unfortunately, we are unable to contact PayPal on your behalf because we do not have direct access to your PayPal account."