Error with SFTP adapter

Question

I am getting following error while trying to poll the data from SFTP location.

The adapter "SFTP" raised an error message. Details "Microsoft.BizTalk.Adapter.Sftp.SftpAdapterException: Failed to get the list of files to download from the SFTP server. ---> System.InvalidOperationException: Session is not opened
at WinSCP.Session.CheckOpened()
at WinSCP.Session.ListDirectory(String path)
at Microsoft.BizTalk.Adapter.Sftp.SftpFileReceiver.PollSftpServer()

Any idea what needs to be change in order to fix this problem?

Answer 1

Try the following, as per my blog article Max worker threads for SFTP, MQSC or DB in BizTalk

1. Have a dedicated host for receive locations using SFTP
2. Increase the Maximum Worker threads setting to 500 on that host instance
3. Check how frequently you poll (the default is 5 seconds), increase the delay if that is not needed.
4. Put a schedule on to only poll during the periods you need.
5. Disable message body tracking if it is not needed.

Answer 2

I have the same error, following Colin´s suggestions did not help in my case
Im using biztalk 2020 CU4 and winscp 15.9.2

I can connect and download files using winscp console though.

Any ideas would be greatly appriciated!

Answer 3

Had the same issue (BizTalk 2016 with latest CU). Increasing the polling interval (5 sec->5min or even more) did the trick.