Reindex, convert float to float, mapper [variableX] cannot be changed from type [float] to [long]

[defalt]

Hi,
I am trying to reindex something. It works with 4/5 of my indcies but the last one fails because of:

{
    "took": 4178,
    "timed_out": false,
    "total": 56576151,
    "updated": 0,
    "created": 994,
    "deleted": 0,
    "batches": 1,
    "version_conflicts": 0,
    "noops": 0,
    "retries": {
        "bulk": 0,
        "search": 0
    },
    "throttled_millis": 0,
    "requests_per_second": -1.0,
    "throttled_until_millis": 0,
    "failures": [
        {
            "index": "index_new",
            "type": "specific_Variable",
            "id": "AW0NVRx9LYYiXtYaus-y",
            "cause": {
                "type": "illegal_argument_exception",
                "reason": "mapper [variableX] cannot be changed from type [float] to [long]"
            },
            "status": 400
        },
        {
            "index": "index_new",
            "type": "variable",
            "id": "AWxaFbxRFrqdVWDKqXmd",
            "cause": {
                "type": "illegal_argument_exception",
                "reason": "mapper [variableY] cannot be changed from type [float] to [long]"
            },
            "status": 400
        },
        .
.
// Happens another 3 times with other variables
.

    ]
}

My Command:

POST /_reindex
{
  "conflicts": "proceed",
  "source": {
    "index": "index"
  },
  "dest": {
    "index":  "index_new",
    "op_type": "create"
  }
}

I tried it with a processor but it didn't help.

{
  "conflicts": "proceed",
  "source": {
    "index": "index"
  },
  "processors" : [
    {
      "convert" : {
        "field" : "variableX",
        "type": "float"
      }
    }
  ],
  "dest": {
    "index":  "index_new",
    "op_type": "create"
  }
}

Any ideas?
Thanks

[defalt]

Solved by creating a mapping for the Index.