Microsoft say this about Winsock error 11001 - WSAHOST_NOT_FOUND:

No such host is known. The name is not an official host name or alias, or it cannot be found in the database(s) being queried. This error may also be returned for protocol and service queries, and means that the specified name could not be found in the relevant database."""

Full details of Winsock TCP error 11001 - WSAHOST_NOT_FOUND:

Berkeley description: No such host is known. The name you have used is not an official hostname or alias. This is not a soft error, another type of name server request may be successful.

WinSock description: Same as Berkeley. Any of the WinSock name resolution functions can fail with this error. The WinSock API does not provide any way to select specific name resolution protocols, server address, or record type.

TCP/IP scenario: Most WinSock implementations use domain name system (DNS) protocol for hostname to address resolution, although a few use Network Information System (NIS). Assuming you have a name server configured instead of or as well as a host table, a hostname resolution request causes a WinSock DLL to send a DNS "A" record query (address query) to the configured DNS query. If you have more than one server configured, the hostname query fails only after the WinSock DLL has queried all servers.

User suggestions: Check that you have a name server(s) and/or host table configured. If you are using a name server(s), check whether the server host(s) are up (e.g. try to ping the server(s)). You could also try to resolve another hostname you know should work, to check that the name resolution server application is running.

If you are using a host table exclusively, you'll need to update it to add the destination hostname and address.