Mods, please move this ticket if I didn’t put it in the right place!  Thanks!

Based on the API documentation found here: https://api.freshservice.com/#create_child_service_request

Note 1:
Association of child Service Request to a deleted or a spammed ticket is not allowed.

Note 2:
Nesting of a child Service Request under another child Service Request is not supported.

I should be able to use this endpoint, passing in a parent ticket id of a Resolved ticket.  

But doing so results in the following error: 

"code":"invalid_id","message":"There is no record matching the id: 1337"

Please either update your documentation or change this behavior.

SOLUTION: The way I got around the issue is by reopening the parent ticket and trying again.