I have already two account in my sandbox and I have created a new test account for test transaction process. I setup API username, password, signature in my website correctly. I have also go to merchant account in sandbox.paypal.com website and changed auto return on and give return website link and Payment Data Transfer (optional) is on, Encrypted Website Payments is off, PayPal Express Checkout Settings is off. When I go to my website https://writenowads.com/ and process paypal sandbox payment and it gives the error "We aren't able to process your payment using your PayPal account at this time. Please go back to the merchant and try using a different payment method." and it tells return to merchant option. I cant do it for sandbox as well as in live account. In my website side developer asking API username, password, signature, and mail id. Please give me a suggestion to solve this problem. I have added content in My Apps & Credentials
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