Service Desk automation Webhooks not populating fields in body

[oglakan]

Jira v7.11.0

Service Desk v3.14.0

I am attempting to use the example from the following tutorial but the issue values are not getting populated.  I have no idea what I am doing wrong.

https://developer.atlassian.com/server/jira/platform/jira-service-desk-webhooks/

I am attempting to post the following to MatterMost:

{
"text": "${issue.key}"
}

I get the following in the matter most channel:

${issue.key}

I also tried using ${request.key} to no avail. 

Thanks in advance.