I am trying to import time_entries from a third party system to OpenProject.

The request body:

{ 
"comment": "Logging time", 
"startTime": "2025-10-13T14:45:00.000Z", 
"endTime": "2025-10-13T16:00:00.000Z", 
"_links": { 
  "project": { "href": "/api/v3/projects/3" }, 
  "entity": { "href": "/api/v3/projects/3/work_packages/56" }, 
  "user": { "href": "/api/v3/users/194" } 
  }, 
"spentOn": "2025-10-13", 
"createdAt": "2025-12-12T19:20:28.059Z", 
"updatedAt": "2025-12-12T19:20:28.059Z" 
}

I think I followed the docs here: https://www.openproject.org/docs/api/endpoints/time-entries/

But I am only getting a non helping error:

{ 
"_type": "Error", 
"errorIdentifier": "urn:openproject-org:api:v3:errors:InternalServerError", 
"message": "An internal error has occurred.undefined method 'end_time=' for an instance of #<Class:0x00007f7c59e199c0>"
}

Does somebody have an explanation what is wrong?

Thanks in advance.