PayPal沙盒新证书提供超时处理请求错误

升级PayPal沙盒，以提供更安全的API证书，具有SHA-2562048位。这是使用中提供的openssl命令进行验证的

现在，当我在sandbox上使用现有的旧（SHA-1，1024位）API证书进行测试时，它工作正常

但当一个新的API证书（SHA-256，2048位）被创建并用于在sandbox上进行测试时，它开始从sandbox发出错误响应

ACK=故障
L_ERRORCODE0=10001
L_SHORTMESSAGE0=内部错误
L_LONGMESSAGE0=超时处理请求

请任何人都指出这个错误的原因是什么

作为发送到sandbox端点的PayPal请求（已修改）的参考

METHOD = SetExpressCheckout
RETURNURL = https://local/ReturnPage
CANCELURL = https://local/ProcessCancel
ALLOWNOTE = 0
LOGOIMG = https://local/img/logo.png
ADDROVERRIDE = 1
EMAIL = xxx@xxx.com
SOLUTIONTYPE = Mark
BUTTONSOURCE = BtnSrc
BRANDNAME = My Brand
PAYMENTREQUEST_0_SHIPTONAME = Mr Joshi
PAYMENTREQUEST_0_SHIPTOSTREET = 300 Oxford Street
PAYMENTREQUEST_0_SHIPTOCITY = London
PAYMENTREQUEST_0_SHIPTOZIP = TE45 6ST
PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE = GB
PAYMENTREQUEST_0_SHIPTOPHONENUM = 09824112345
NOSHIPPING = 1
PAYMENTREQUEST_0_PAYMENTACTION = Sale
PAYMENTREQUEST_0_CURRENCYCODE = GBP
L_PAYMENTREQUEST_0_NAME0 = 101-Jeans
L_PAYMENTREQUEST_0_DESC0 = Jeans
L_PAYMENTREQUEST_0_AMT0 = 59.0
L_PAYMENTREQUEST_0_QTY0 = 1
L_PAYMENTREQUEST_0_NAME1 = Other payments
L_PAYMENTREQUEST_0_DESC1 = Other payments
L_PAYMENTREQUEST_0_AMT1 = -8.02
L_PAYMENTREQUEST_0_QTY1 = 1
PAYMENTREQUEST_0_ITEMAMT = 50.98
PAYMENTREQUEST_0_AMT = 53.97
PAYMENTREQUEST_0_SHIPPINGAMT = 2.99
MAXAMT = 53.97
VERSION = 112.0

我已经双重验证了API用户名和API密码。以及API证书。甚至从sandbox帐户下载cert_key_pem.txt获得API证书，然后重新创建API证书