help me about Express Checkout api

[Monakol]

i send api https://api-3t.paypal.com/nvp and palpay return error

SetExpressCheckout failed: Array (
[TIMESTAMP] => 2018-10-10T06:20:42Z
[CORRELATIONID] => 698211fb186e7
[ACK] => Failure
[VERSION] => 74.0
[BUILD] => 49581750
[L_ERRORCODE0] => 10004
[L_SHORTMESSAGE0] => Transaction refused because of an invalid argument See additional error messages for details
[L_LONGMESSAGE0] => You are not signed up to accept payment for digitally delivered goods
[L_SEVERITYCODE0] => Error )

how i can fix it ?

[angelleye]

Sounds like you're including digital goods parameters in your request, but your account is not configured for that.

Please post a sample of a request you are sending that is generating this result.