Sftp error - Dying because - Idle connection

I am trying to download files from sftp which are larger in size either 10 gb or more. while the first file is getting downloaded it throws below error then it doesn’t try to download the next file.
20/03/27 19:07:28 INFO net.schmizz.sshj.transport.TransportImpl: Received SSH_MSG_DISCONNECT (reason=BY_APPLICATION, msg=Idle connection)
20/03/27 19:07:28 ERROR net.schmizz.sshj.transport.TransportImpl: Dying because - Idle connection
net.schmizz.sshj.transport.TransportException: [BY_APPLICATION] Idle connection
at net.schmizz.sshj.transport.TransportImpl.gotDisconnect(TransportImpl.java:548)
at net.schmizz.sshj.transport.TransportImpl.handle(TransportImpl.java:508)
at net.schmizz.sshj.transport.Decoder.decode(Decoder.java:102)
at net.schmizz.sshj.transport.Decoder.received(Decoder.java:170)
at net.schmizz.sshj.transport.Reader.run(Reader.java:59)
20/03/27 19:07:28 INFO net.schmizz.sshj.transport.TransportImpl: Disconnected - BY_APPLICATION

Below is the code

val ftpGraph = (sftpFile: FtpFile, sftpSettings: SftpSettings) =>
Sftp.fromPath(sftpFile.path, sftpSettings)
.completionTimeout(3000 second)
.idleTimeout(3000 second)
.addAttributes(Attributes.logLevels(onFailure = Attributes.LogLevels.Debug))
.to(FileIO.toPath(Paths.get(tempDir + “/” + sftpFile.name)))
val fileFlow =
Flow[FtpFile].mapAsync(parallelism = 1) { sftpFile =>
println(“Processing SFTP file: " + sftpFile.path)
for {
ftpResult <- ftpGraph(sftpFile, sftpSettings).run
if ftpResult.wasSuccessful
csv <- unzipGraph(sftpFile, tempDir).run
csvFile <- gcpUploadGraph(csv, conf.gcpCsvPath + “/” + csv.substring(csv.lastIndexOf(”/") + 1, csv.length)).run
ignore <- cleanupGraph(sftpFile, sftpSettings, csv).run
} yield s"Upload from ${sftpFile.path} to $ftpResult.wasSuccessful successful"

  val fileSink = Sink.foreach[String] { s =>
    println("fileSink: " + s)

  val finalStep = Sftp.ls("/gets/", sftpSettings)
    .initialTimeout(300 second )
    .addAttributes(Attributes.logLevels(onElement = Attributes.LogLevels.Debug))

Hi @kumargaurav.cdac,

that looks as if the peer had decided that nothing is going on in the connection and therefore closed it. Hard to say why the connection gets stalled, maybe something else is going on in your application that prevents the SFTP connection from making progress (quickly enough)?

I’d try to watch the bandwidth usage while downloading and when it plummets, I’d try to gather a stack trace (e.g. with jstack <pid> on the command line) to see what the application is doing.