When running Cascade CMS 8.0 or below, the following error message may appear when attempting to publish via SFTP:
SFTP error occurred during SFTP Shuttle initialization: Algorithm negotiation fail
This message indicates that the target web server does not support the
diffie-hellman-group1-sha1 key exchange method (typically if OpenSSH on the web server is upgraded to version 6.7+).
There are 3 options for resolving this:
Re-enable the disabled algorithm (diffie-hellman-group1-sha1) on your web server.
Upgrade the SFTP library within Cascade CMS to a more recent version which supports the latest exchange algorithms. To do so, follow these steps:
Download the latest JSCH .jar file
Stop Cascade CMS
Back up the existing jsch-0.1.42.jar in tomcat/webapps/ROOT/WEB-INF/lib and then replace it with the new one
3. Upgrade to Cascade 8.0.1 (or higher). Newer versions of Cascade CMS have an updated SFTP library that includes support for the latest key exchange methods.