API REST returns Error null creating a subtask

[Jorge Lozano]

Dear Sirs,

I’m trying to create tasks and subtasks using the API REST on JIRA JIRA v6.2.3. It seems to works fine for Tasks, but  not for subtasks. For subtasks creation JIRA always returns "Error al crear la incidencia: null" without more explanations.

I checked necessary fields on subtask, id of subtask exists, etc. Tried to do not provide some of the parameters on the creation JSON subtask request and in all cases returns an explanation message about what is missing, but when it seems that all parameters are informed and ready to create a subtasks it fails an returns error null and status 400 Bad Request.

 Here is the JSON request and response I used for subtask creation

Request
{
    "fields":
    {
        "project":
        {
            "key": "IMM"
        },
        "parent":
        {
            "key": "IMM-5310"
        },
        "summary": "Sub-task of IMM-5310",
        "description": "Don't forget to do this too.",
        "issuetype":
        {
            "id": "19"
        }
    }
}
 
Response
{
    "errorMessages": [
        "Error al crear la incidencia: null"
    ],
    "errors": {}
}

Thanks in advance!!

[Jeff Grant]

I'm just starting to get this problem now as well.

I have an automated system that creates a series of tasks and sub-tasks, and it's worked just fine for weeks, but today it fails with a "Bad Request" 400 error.

Nothing on my end has changed.