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I am using the PayPal sandbox to make test payments. It was working fine since last 3-4 months. But I see that they are making changes in sandbox design, ways to manage test email accounts, etc.
They have disabled my actual sandbox account and asks me to login using real PayPal account. So I created a new sandbox (https://developer.paypal.com/) account using my PayPal account. I imported test emails from my old sandbox account, and started making test payments. But it didn't work. I deleted all my imported test emails, and created some new test emails. But it also didn't work.
I am logged into the sandbox account, try to make a test payment. But it shows me this message everytime.
I am not getting what's the issue. Need help please.
Thanks in advance.
Before opening up a browser, clear all of your cookies and cache on your browser. There have been some issues with having cookies from the old developer site, and using the new developer site. Also there has more issues with IE than with Firefox and Chrome. So you may want to try using Firefox or Chrome as well, but make sure you clear your cookies and cache prior to opening up the browser and going to the developer.paypal.com site.
来源：https://stackoverflow.com/questions/15476607/paypal-sandbox-not-working