Issues - Capistrano::ConnectionErr

$ cap deploy   * executing `deploy'
  * executing `deploy:update'
 ...........
** [deploy:update_code] exception while rolling back: Capistrano::ConnectionError, connection failed for: example.com (Net::SSH::HostKeyMismatch: fingerprint xx:xx:xx:xx:xx:xx:xx:xx:xx does not match for "example.com")
connection failed for: example.com (Net::SSH::HostKeyMismatch: fingerprint xx:xx:xx:xx:xx:xx:xx:xx:xx does not match for "example.com")

To fix this issue go to known_hosts file of the user. Example /home/deployer/.ssh/known_hosts and remove the domain specific entry. In this case domain is "example.com".

Domain specific entry would be like this - example.com ssh-rsa BBBAE5Uz

Hope this may help you