GlobalSCAPE Knowledge Base

SFTP21 error = #4 (No further authentication methods available)

GlobalSCAPE Support 1


  • CuteFTP Pro® (All Versions)


When attempting a connection using the SFTP protocol, the following error is encountered:

STATUS:>   Getting listing ""...

STATUS:>   Initializing SFTP21 module...

STATUS:>   Connecting to SFTP server... (ip =

ERROR:>    No further authentication methods available.

ERROR:>    The requested operation failed for an unknown reason.

ERROR:>    Can't connect to SFTP21 error = #4.

STATUS:>   SFTP21 connection closed.


  1. The SFTP server is configured to use a Message Authentication Code (MAC) that does not match the MAC configuration settings in CuteFTP Pro or is not supported in CuteFTP Pro.
  2. CuteFTP Pro may be providing the server with the wrong public key.
  3. The remote FTP site may be expecting a password in addition to the public key.
  4. The user may not have sufficient account privileges on the remote server. 


  1. Configure the SSH2 security settings in CuteFTP Pro so the requested MAC can be used.  If the SFTP server is using an unsupported MAC, ask the administrator of the remote FTP server to allow use of a different MAC.  CuteFTP Pro supports SHA-1 (128), SHA-1-96, MD-5 and MD-5-96.
  2. If you have previously configured CuteFTP Pro to use more than one public key, ensure that the correct public key for this site is selected in the CuteFTP Pro SSH2 security settings area.
  3. If the remote FTP site is expecting a password in addition to a public key, ensure that option is enabled in the CuteFTP Pro SSH2 security settings area.
  4. Ensure that the user account on the remote FTP server is configured with List and Show in List permissions.

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Last Modified: 7 Years Ago
Last Modified By: GlobalSCAPE 5
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