Recent OpenSSH servers running on ubuntu use the following key exchange algorithms
When using the current version (1.13) which uses jsch 0.1.45 the plugin will fail with the message "Algorithm negotiation failed". Bumping the dependency to 0.1.53 solves the problem as i.e. diffie-hellman-group-exchange-sha256 was enabled by default in 0.1.51.
I rebuilt the 1.13 version with jsch 0.1.53 and it works fine on our Jenkins cluster. Please bump this dependency.