I'm trying to create a Chained payment flow in my site.I receive always the Error 520003 Authentication Failed. I have found many solutions on the web but anything seems works for me. This his my header request: [0] => X-PAYPAL-SECURITY-USERID: developer_api1.gmail.com
[1] => X-PAYPAL-SECURITY-PASSWORD: xxxxxxxx
[2] => X-PAYPAL-SECURITY-SIGNATURE: xxxxxxxxx
[3] => X-PAYPAL-SECURITY-SUBJECT: subject
[4] => X-PAYPAL-REQUEST-DATA-FORMAT: XML
[5] => X-PAYPAL-RESPONSE-DATA-FORMAT: XML
[6] => X-PAYPAL-APPLICATION-ID: APP-80W284485P519543T
[7] => X-PAYPAL-DEVICE-ID:
[8] => X-PAYPAL-DEVICE-IPADDRESS: http://192.168.1.9:8888
[9] => X-PAYPAL-SANDBOX-EMAIL-ADDRESS: developer_mail@gmail.com The api credentials i use are correct. I get user,password and key from the business test user in developer.paypal site. The developer mail is the real address i use to log in developer.paypal site to create test accounts. How i can do?
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