I am getting an error message when using the Azure DevOps REST API (regardless of version).

Running POST https://dev.azure.com/{organisation}/{project}/_apis/wit/classificationnodes/Areas?api-version=7.1-preview.2

with a body payload

{
“name”: “Very nice area”
}

Does not execute and an error is returned.

“status”: 415,
“message”: “TF400898: An Internal Error Occurred…..

From the MS article below I’d expect to have an Area created for the given Organisation and project in the URL. Note that I do not have an issue using other REST API calls to the same DevOps organisation.

https://learn.microsoft.com/en-us/rest/api/azure/devops/wit/classification-nodes/create-or-update?view=azure-devops-rest-7.2&tabs=HTTP

I’ve tried adding the path in the body and the URL and various versions of the API. I’m able to update work items in the same organisation. I also get the same error when trying Iterations as well as Area.