下面的代码添加到您的web.config：

Add the following tag to your web.config:

<configuration>
    <system.web>
       <trust level="Full" />
    </system.web>
</configuration>

这是您的托管服务的服务器可能是设置具有中等信任级别。在'PayPalCoreSDK'是要求应用程序具有完全信任级别运行。

The servers on your hosting service is probably setup with a medium trust level. The 'PayPalCoreSDK' is requires your application to run with a full trust level.