🐛[BUG] Dropbox加速经常不能用

### 🐛 描述(Description)

### 📷 复现步骤(Steps to Reproduce)

1. 加速dropbox
2. 打开dropbox.com
3. 进不去了

### 📄 [异常/日志]信息([Exception/Log] Information)
2022-07-20 07:58:40.6166|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to www.dropbox.com 162.125.69.1:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
2022-07-20 07:59:32.8775|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to www.dropbox.com 162.125.69.1:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
2022-07-20 07:59:53.7600|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to www.dropbox.com 162.125.69.1:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
2022-07-20 08:01:29.6182|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to github.com 20.205.243.166:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
2022-07-20 08:01:31.4631|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to github.com 20.205.243.166:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
2022-07-20 08:01:36.0393|Error|HttpProxyS|ProxyServer ExceptionFunc | Titanium.Web.Proxy.Exceptions.ProxyHttpException: Error occured whilst handling session request
---> System.Exception: Could not establish connection to github.com 20.205.243.166:443
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.createServerConnection(String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, SslProtocols sslProtocol, List`1 applicationProtocols, Boolean isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, String cacheKey, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, String remoteHostName, Int32 remotePort, Version httpVersion, Boolean isHttps, List`1 applicationProtocols, Boolean isConnect, SessionEventArgsBase sessionArgs, IPEndPoint upStreamEndPoint, IExternalProxy externalProxy, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.Tcp.TcpConnectionFactory.GetServerConnection(ProxyServer proxyServer, SessionEventArgsBase session, Boolean isConnect, List`1 applicationProtocols, Boolean noCache, Boolean prefetch, CancellationToken cancellationToken)
at Titanium.Web.Proxy.Network.RetryPolicy`1.ExecuteAsync(Func`2 action, Func`1 generator, TcpServerConnection initialConnection)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(SessionEventArgs args, TcpServerConnection serverConnection, SslApplicationProtocol sslApplicationProtocol, CancellationToken cancellationToken, CancellationTokenSource cancellationTokenSource)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
--- End of inner exception stack trace ---
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleHttpSessionRequest(ProxyEndPoint endPoint, HttpClientStream clientStream, CancellationTokenSource cancellationTokenSource, TunnelConnectSessionEventArgs connectArgs, Task`1 prefetchConnectionTask, Boolean isHttps)
at Titanium.Web.Proxy.ProxyServer.handleClient(TransparentBaseProxyEndPoint endPoint, TcpClientConnection clientConnection, Int32 port, CancellationTokenSource cancellationTokenSource, CancellationToken cancellationToken)
### 🚑 基本信息(Basic Information)

- 程序版本(Program Version):v2.7.2
- 系统版本号(OS Version): Windows 11 22000,795
- 是否为应用商店版本(Whether it is a Store version): nope

### 🖼 截图(Screenshots)


No source file, test, or implementation entry point is identified in the issue. Start by tracing the Dropbox acceleration path and the Titanium.Web.Proxy connection failures for www.dropbox.com:443; done means reproducing the failure and confirming Dropbox can be opened reliably through acceleration.

Written by the indexing model from the issue text.