Error on install via composer on Linux

[Smart-Core]

composer require alb/twig-reflection-bundle:*

composer.json has been updated
Loading composer repositories with package information
Updating dependencies

• Installing alb/twig-reflection-bundle (dev-master c739b5e)
  Cloning c739b5e
  Cloning failed using an ssh key for authentication, enter your GitHub credentials to access private repos
  The credentials will be swapped for an OAuth token stored in /root/.composer/config.json, your password will not be stored
  To revoke access to this token you can visit https://github.com/settings/applications
  Username:

[jeremymarc]

composer/composer#1570