Facing issue in Loadrunner HTTP Status-Code=403 (Forbidden)

Facing issue in Loadrunner HTTP Status-Code=403 (Forbidden) for “https://www.sandbox.paypal.com/signin” [MsgId: MERR-26628]

If i change the method from POST to GET, script gets success but in the transaction list page status is awaiting state, the payment is not successful.

Note: When i do the payment manually then transaction status is in completed state and payment is done successful.

web_submit_data("signin_2",
        "Action=https://www.sandbox.paypal.com/signin",
        "Method=GET",
        "EncodeAtSign=YES",
        "RecContentType=application/json",
        "Referer=https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=EC-1B7670629N2587031#/checkout/login",
        "Snapshot=t38.inf",
        "Mode=HTTP",
        ITEMDATA,
        "Name=_csrf", "Value=9KmCQA6iJyMUVkA8hTTmTWQ51ZMTXrb9iDSF0=", ENDITEM,
        "Name=_sessionID", "Value=uwviv5VWRizd5CSVlkVEIcl9dgn55t5U", ENDITEM,
        "Name=locale.x", "Value=en_US", ENDITEM,
        "Name=dt_stsRedirectUri", "Value=https://www.sandbox.paypal.com/checkoutnow/2", ENDITEM,
        "Name=dt_rememberMe", "Value=true", ENDITEM,
        "Name=dt_flowId", "Value=EC-1B7670629N2587031", ENDITEM,
        "Name=dt_originalUrl", "Value=/signin/inject/?stsRedirectUri=https%3A%2F%2Fwww.sandbox.paypal.com%2Fcheckoutnow%2F2&country.x=US&locale.x=en_US&rememberMe=true&flowId=EC-1B7670629N2587031&returnUri=https%3A%2F%2Fwww.sandbox.paypal.com%2Fcheckoutnow%2F2&state=%3Fflow%3D1-P%26token%3DEC-1B7670629N2587031&requestFrom=server", ENDITEM,
        "Name=returnUri", "Value=https://www.sandbox.paypal.com/checkoutnow/2", ENDITEM,
        "Name=state", "Value=?flow=1-P&token=EC-1B7670629N2587031", ENDITEM,
        "Name=login_email", "Value=xxxxxxxxxxxxxxxxxxxxxxxx", ENDITEM,
        "Name=login_password", "Value=xxxxxxxxxxxxxxxx", ENDITEM,
        "Name=rememberMe", "Value=true", ENDITEM,
        LAST);