Random approvals, declines, and timeouts usually result when the credit card numbers you're using are associated with many test accounts. The system has difficulty handling multiple requests for these same numbers. You must use a unique credit card number when performing test credit card transactions with a Payflow Pro account linked to a Sandbox account. There are two ways to do this:

Use the credit card number assigned to your Sandbox test account.

When you create a new Sandbox test account on our Developer site, the account is assigned a unique credit card number, and you can use any three-digit number as the card verification number.

Here's how to create a test account:

1. Log in to the PayPal Developer Portal.
2. Navigate to Testing Tools > Sandbox Accounts.
3. Click Create Account and complete the process.

Credit card generator for testing:

You can use our credit card generator to create a credit card number and associate it with a Sandbox account. Here’s how:

1. Go to your sandbox Money, banks and cards page.
2. Click Link a new card.
3. Enter the card details obtained from our credit card generator.

How do you log in to your Sandbox account?

See the Sandbox accounts Developer Documentation.