Ansible 2.9.2 errors

[anthonyangel]

ansible 2.9.2
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.15+ (default, Oct  7 2019, 17:39:04) [GCC 7.4.0]

I'm trying to run this from an Ubuntu 18 host, but getting the following errors:
Couldn't send event "Ansible task changed on "hostname"" to Datadog
API key is not set. Please run 'initialize' method first.

My API key is set via the DATADOG_API_KEY env var

[anthonyangel]

At the start of the run, I get the following error:
Failure using method (v2_playbook_on_play_start) in callback plugin (<ansible.plugins.callback.datadog_callback.CallbackModule object at 0x7f9562f55a10>): mapping values are not allowed here in datadog_callback.py, line 8, column 4