The new environment name must be purely alphanumeric

[ghost]

For example, if you choose for environment name something like:
atomia2.local
atomiatest.com

Puppet will complain with:
Could not request certificate: Error 400 on SERVER: The environment must be purely alphanumeric, not 'atomiatest.com'

This is what I expirienced during installation of test environment. Nothing worng with this, except the page should be descriptive in regards to what is allowed and what is not.