title: Cassandra-sharp exception "Can't find any valid endpoint"
body: <p>I'm trying to connect Cassandra cluster with cassandra-sharp .Net client driver, but I get an exception <strong>&quot;Can't find any valid endpoint&quot;</strong>. When I execute sample client code as it is on cassandra-sharp github (<em><a href="https://github.com/pchalamet/cassandra-sharp" rel="nofollow noreferrer">https://github.com/pchalamet/cassandra-sharp</a></em>), I get an error on any operation after opening connection to cluster, such as this <em>Execute</em> command:</p>
  <pre><code>using (ICluster cluster = ClusterManager.GetCluster(&quot;Cassandra&quot;))
  {   
      ICqlCommand cmd = cluster.CreatePocoCommand();
      Task t = cmd.Execute(&quot;Select * from system_schema.keyspaces&quot;).AsFuture();
  ...}
  </code></pre>
  <p>When I start debugging this line, I see all my endpoints in view of tree <em>ICluster -&gt; SingleConnectionPerEndpointStrategy -&gt; _endpointStrategy -&gt; NearestEndpointStrategy -&gt; bannedEndpoints</em> (with list of my IP-adresses), and 0 endpoints are healthy.</p>
  <p>Moreover, when I'm trying to connect to any of my hosts with <em>cqlplus.exe</em> utility (from cassandra-sharp driver binaries), I get same error. With <em>/dbglog</em> flag it shows messages like this:</p>
  <blockquote>
  <p>Creating connection to 192.168.1.3</p>
  <p>Readyfying connection for 192.168.1.3</p>
  <p>Starting writing frame for stream 127@192.168.1.3</p>
  <p>Done writing frame for stream 127@192.168.1.3</p>
  <p>Failed building connection System.AggregateException: One or more errors occurred. ---&gt; System.OperationCanceledException: The operation was canceled.</p>
  <p>--- End of inner exception stack trace ---</p>
  <p>at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)</p>
  <p>at CassandraSharp.Transport.LongRunningConnection.ReadifyConnection() in ...\LongRunningConnection.cs:line 444</p>
  <p>...
  Error creating transport for endpoint 192.168.1.3 : One or more errors occurrd.</p>
  <p>... - marking 192.168.1.3 for recovery</p>
  <p>Command execution failed with error:
  Can't find any valid endpoint</p>
  </blockquote>
  <p>I use latest version of cassandra-sharp driver 3.7.0 and Cassandra version 3.11.0. My <em>App.config</em> file seems like ok. And the code is ideal, so it may be wrong configuration of the cluster. Network is simple with one switch, everything pinged, all Cassandra ports are opened in Windows firewall on the client PC. I can add any needed additional information from the config file <em>cassandra.yaml</em>, f.e. I use <em>PropertyFileSnitch</em>. In <em>cqlsh</em> console everything works fine, <em>nodetool status</em> is Up&amp;Normal.</p>
  <p>So is it something wrong with configuration of my cluster or with .Net driver, and how to solve it? Need help of Cassandra specialists. Thank you!</p>