System.Net.WebException: 基础连接已经关闭: 未能为 SSL/TLS 安全通道建立信任关系。 ---> System.Security.Authentication.AuthenticationException: 根据验证过程，远程证书无效。 在 System.Net.Security.SslState.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, Exception exception) 在 System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) 在 System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) 在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) 在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) 在 System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result) 在 System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size) 在 System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size) 在 System.Net.ConnectStream.WriteHeaders(Boolean async) --- 内部异常堆栈跟踪的结尾 --- 在 System.Net.HttpWebRequest.GetResponse() 在 EtCommonBase8.Common.Helper.GetPageContent(String url, String postdata, String encode, String method)