Jira Cloud API V2 - Project Template Unavailable

[Deleted user]

When attempting to create a project via the V2 API , I receive the following error:

The project template specified does not exist. Make sure the project template is available in your Jira instance. Please talk to your Jira administrator if you need more help

I've set the projectTypeKey: software and projectTemplateKey: com.pyxis.greenhopper.jira:gh-simplified-scrum. This had been working previously, but not sure if there were recent changes that are causing this to be broken.