Cannot get Server/Tentacle to Connect

We have an environment which is firewalled from our octopus server, when we add a tentacle to a box in that environment we are seeing the following error in the logs. Any help would be greatly appreciated.

2014-01-27 15:52:19.1827 ERROR Client failed authentication
System.Security.Authentication.AuthenticationException: A call to SSPI failed, see inner exception. —> System.ComponentModel.Win32Exception: The client and server cannot communicate, because they do not possess a common algorithm

— End of inner exception stack trace —
at System.Net.Security.SslState.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, Exception exception)

at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)

at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
at Pipefish.Transport.SecureTcp.Server.SecureTcpServer.ExecuteRequest(TcpClient client) in c:\TeamCity\buildAgent\work\cf0b1f41263b24b9\source\Pipefish.Transport.SecureTcp\Server\SecureTcpServer.cs:line 109

Hi Jonathan,

Is it possible there’s a web proxy between the two machines? Communication needs to be direct between the server and the Tentacle’s communication port, proxies aren’t supported in v2.

If there’s no proxy, can you please try browsing to the Tentacle’s communication port with a web browser? There are some instructions at:


This seems to have just solved itself. Not sure what was going on.

Great - glad to hear.