Give CSPSystem user access to the database with a REST broker.

Just use a service with EnsLib.File.InboundAdapter.

How many files are there in total?

How many (on average) do you need to process per day?

@Yuri Marx you can use "@Name" to mention someone.

@Sarvesh Raut is your server available over HTTPS (and call HTTPS endpoints)?

Please post the code of GatewayState method.

Calling @Luca Ravazzolo 
 

Please file a WRC ticket?

Not really.

Object ByRef means pointer itself may be changed (so we need to pass a pointer to a pointer), which is exactly what happens in this method.

A more correct qualifier would be Output as old object is always discarded.

But initializing stfp before the call would serve no purpose in this case.

Remote path should be just:

set remotePath="/NEW.txt"

That said, this error

Ошибка '-2147014836': A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.   

looks like you don't have the network connectivity. Have you tried to connect with Putty from the same server as Ensemble?

Docs specify that Connect should come before Authentication.

Try this code:

Try {
    Set ssh = ##class(%Net.SSH.Session).%New()

    Set sc = ssh.Connect(host)
    Write:$$$ISERR(sc) "Connect:", $System.Status.GetErrorText(sc),!
    
    Set sc = ssh.AuthenticateWithUsername(username, password)
    Write:$$$ISERR(sc) "Auth: ", $System.Status.GetErrorText(sc), !
    
    #dim sftp As %Net.SSH.SFTP
    Set sc = ssh.OpenSFTP(.sftp)
    Write:$$$ISERR(sc) "SFTP: ", $System.Status.GetErrorText(sc), !
    
    Set sc = sftp.Dir("/", .contents, , $$$YES)
    Write:$$$ISERR(sc) "Dir: ", $System.Status.GetErrorText(sc), !
    
    Zwrite contents
    
    //If 'sftp.Disconnect() Write "Failed to logout",!

} Catch ex {
    Set sc = ex.AsStatus()
    Write "Exception: ", ex.DisplayString(), !
}

dc?