How do I Use Ansible Automation Platform Notifications from Behind a Proxy?

Issue

• When attempting to send notifications from Ansible Automation Platform (AAP) to remote services like Slack or Hipchat when AAP is behind a proxy, the notifications will fail.
• Testing a notification template from the automation controller UI fails with a ConnectionError.
• The destination endpoint is reachable with a manual curl from the controller nodes, but the notifier fails.

• The task log shows the failure during the TLS handshake:

  ERROR awx.main.tasks.system Send Notification Failed ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer'))
  ...
  ConnectionResetError: [Errno 104] Connection reset by peer