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SFTP Test connectivity fails with PPK



SFTP connection using PPK file fails.

Error Messages

Status: Fail
Message: Unable to connect

Caused by:
com.jcraft.jsch.JSchException: Session.connect: Prime size must be multiple of 64, and can only range from 256 to 2048 (inclusive) at com.jcraft.jsch.Session.connect(

Steps to Reproduce

  1. Create an FTP Server rule with a KeyStore file.
  2. Customize the Data-Admin-Security-KeyStore.Validate activity to suppress the PPK validation.
  3. Click Test Connectivity.

Root Cause

A defect or configuration issue in the operating environment.
The default SFTP server port is 22; however the server was customized to a different port number.


As a local-change, modify the SFTP port number to the default port number.

Suggest Edit

Published April 29, 2018 - Updated October 8, 2020

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