net-ssh and openssl-3.0.0

You'll need openssl-3 or newer for servers running 22.04

Ruby version 3.1 uses by default the gem openssl-3.0.0. This can cause issues with the gem net-ssh (6.1.0). This is a known bug Show archive.org snapshot .

Typically this can cause an error while deploying an application with capistrano:

Copycould not verify server signature (SSHKit::Runner::ExecuteError)

or

CopyEd25519::VerifyError: signature verification failed!

As temporary workaround add the following line to your Gemfile:

Copygem 'openssl', '<3'

For more information check the compatibility notes Show archive.org snapshot .

Fix

Update net-ssh to version 7 or newer!

Copybundle update net-ssh --conservative

Bundler attempted to update net-ssh but its version stayed the same

Some of your gems prevented net-ssh from updating, update them first. Check your Gemfile.lock to find the gem that prevents you from updating and update this gem first.
bundle update net-scp --conservative