single encrypted vault variable not working

I’m running ansible 2.3.0.0,and attempting to use an inline encrypted variable per this documentation:
http://docs.ansible.com/ansible/playbooks_vault.html#running-a-playbook-with-vault

this structure:

mysecret: !vault |
          $ANSIBLE_VAULT;1.1;AES256
          66386439653236336462626566653063336164663966303231363934653561363964363833313662
          6431626536303530376336343832656537303632313433360a626438346336353331386135323734
          62656361653630373231613662633962316233633936396165386439616533353965373339616234
          3430613539666330390a313736323265656432366236633330313963326365653937323833366536
          34623731376664623134383463316265643436343438623266623965636363326136

yields this error:
ERROR! Syntax Error while loading YAML.

The error appears to have been in '/home/Q2DC/jjolet/ansible-operations/configure/group_vars/nomad-servers-stg.yml': line 13, column 14, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

q2docker_file: "q2docker1.2.1"
vault_token: !vault |
             ^ here


so according to that documentation: 
you just have to be sure to add the !vault tag so both Ansible and YAML are aware of the need to decrypt.

i've installed ansible via yum:
rpm -qa|grep ansible
ansible-2.3.0.0-3.el7.noarch

was there something else that needed to be updated for the yaml parsing to succeed with the encrypted variable?

You get this error message if you don't provide a vault password.