How to log in in Sandbox Paypal Account?

Go to https://www.sandbox.paypal.com , then key in your account which create automatically when you register via https://developer.paypal.com

The new developer accounts require that you first log in using a live PayPal account email address and password. Once you log in you can recover your test accounts by following the steps below.

• Log into https://developer.paypal.com
• Click Applications
• Click Sandbox accounts
• Click "Import data"
• Enter your email address and password for the old developer account.

Since you've had access to the legacy developer account you'll also need to delete your cookies and cache. Strangely enough, if you don't there will be several issues with logging into the account or accessing the test accounts. This will also resolve the invalid email error.

Let me know if you have any issues after this.

You can login here for paypal's sandbox environment https://www.sandbox.paypal.com/us/home