Recurring error when attempting to link jira sub task ticket with parent ticket through confiforms.

[Benjamin Rios]

Hi Atlassian community, I am attempting to link a subtask with a parent task in Confiforms; however, when I go to create the ticket, I am getting the following error:

• Could not prepare JSON: 
  '
  { 
  "fields": 
  
  { 
  "project": {"key": "TEST"},
  
  "parent": { "key": "TEST-3333" }, 
  
  "assignee": {"name":"some_person"}, 
  "priority": {"name": "P1 - Crucial"}, 
  "issuetype": {"name": "Sub-task"},
  
  "summary": "Test Ticket: Update expiring information for: Some Person", 
  "duedate": "2027-12-19", 
  "labels": ["expiration"], 
  } 
  }
  '. 
  
  Invalid format. Expected a ':' after a key at 9 [character 7 line 2]

I am not sure where exactly I am missing a colon, but I believe I have mapped my fields as outlined in: https://developer.atlassian.com/server/jira/platform/jira-rest-api-examples/#creating-an-issue-examples

In any case, if there is something obvious that I am missing, I would much appreciate any help. 

Thank you!