SAP Knowledge Base Article - Public

2552624 - Failed to connect to SFTP server with "ssh_exchange_identification" error


We failed to connect to SFTP server, by checking logs error like "ssh_exchange_identification: Connection closed by remote host..." was observed.

Reproducing the Issue

Login to SFTP server with provided user account name and password, failed to login, customer can see error with SFTP connection on their side.


There's various causes which could lead to such error with SFTP connection including but not limited to:

  • The IP address of the customer has been blocklisted in our SFTP server due to some issue
  • Customer performed login with wrong credentials over multiple times which auto-banned customer's public IP
  • SSHD's Host Keys are corrupted for some reason

Note that each time the situation could be different even for same error, but most time we need error log in verbose mode to analyse root cause.


Usually for "ssh_exchange_identification: Connection closed by remote host" issue all troubleshooting start from client side, restarting sshd daemon usually fix this kind of issue. And if issue persists, please gather error log in verbose mode and provide the log details to us with a support incident, our operation team will be able to make analysis to identify the root cause from server side.

You can run this command for log details:

sftp -vvv

(for example sftp -vvv


KBA , LOD-SF-PLT-FTPE , SFTP Error , Problem


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