我正在尝试进行SOAP Web服务调用（AdaptiveAccounts Service和CreateAccount操作）。在调用webservice时，我收到Authentication错误（身份验证失败.API凭据不正确。） 我正在使用沙盒帐户创建时提供的API凭据，但无法确定具体问题。如果请求有任何问题，请告诉我。 请为此提出解决方案。 以下是我的请求和响应XML。
========================REQUEST XML=========================
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:urn="urn:ebay:api:PayPalAPI" xmlns:urn1="urn:ebay:apis:eBLBaseComponents">
<SOAP-ENV:Header>
<urn:RequesterCredentials>
<urn1:Credentials>
<urn1:Username>SandboxUsername</urn1:Username>
<urn1:Password>SandboxPassword</urn1:Password>
<urn1:Signature>AFcWxV21C7fd0v3bYYYRCpSSRl31ADYp5gFqA3XsQwuoGCUc3wgZHitU
</urn1:Signature>
</urn1:Credentials>
</urn:RequesterCredentials>
</SOAP-ENV:Header>
<SOAP-ENV:Body xmlns:ns2="http://svcs.sandbox.paypal.com/services">
<ns2:CreateAccountRequest>
<requestEnvelope>
<errorLanguage>en_US</errorLanguage>
</requestEnvelope>
<accountType>PERSONAL</accountType>
<emailAddress>testing1-2039@paypal.com</emailAddress>
<name>
<firstName>Srikanth</firstName>
<lastName>Rao</lastName>
</name>
<dateOfBirth>1968-01-01Z</dateOfBirth>
<address>
<line1>1968 Ape Way</line1>
<line2>Apt 123</line2>
<city>Austin</city>
<state>TX</state>
<postalCode>78750</postalCode>
<countryCode>US</countryCode>
</address>
<contactPhoneNumber>888-555-1212</contactPhoneNumber>
<currencyCode>USD</currencyCode>
<citizenshipCountryCode>US</citizenshipCountryCode>
<preferredLanguageCode>en_US</preferredLanguageCode>
<notificationURL>http://...</notificationURL>
<registrationType>WEB</registrationType>
<createAccountWebOptions>
<returnUrl />
</createAccountWebOptions>
</ns2:CreateAccountRequest>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
=========================================================================
=============RESPONSE XML============================================
<?xml version='1.0' encoding='utf-8'?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Header />
<soapenv:Body>
<soapenv:Fault xmlns:axis2ns245141="http://schemas.xmlsoap.org/soap/envelope/">
<faultcode>axis2ns245141:Server</faultcode>
<faultstring>Authentication failed. API credentials are incorrect.</faultstring>
<detail>
<ns4:FaultMessage xmlns:ns4="http://svcs.paypal.com/types/common"
xmlns:ns2="http://svcs.paypal.com/types/aa">
<responseEnvelope>
<timestamp>2015-04-15T11:14:16.838-07:00</timestamp>
<ack>Failure</ack>
<correlationId>8b0f4547f0ea8</correlationId>
<build>13599725</build>
</responseEnvelope>
<error>
<errorId>520003</errorId>
<domain>PLATFORM</domain>
<subdomain>Application</subdomain>
<severity>Error</severity>
<category>Application</category>
<message>Authentication failed. API credentials are incorrect.
</message>
</error>
</ns4:FaultMessage>
</detail>
</soapenv:Fault>
</soapenv:Body>
</soapenv:Envelope>
===================================================================