Is there any Dojo treegrid limits to avoid "Sorry, an error occurred" message appear?

I cannot find any info if there is any limitations for dojo treegrid JSON store. Here is my simple store. It works perfect but fails if it has thousands of items. So is there a limit for number of items or childItems? Or is there a limit for JSON object size?

{
  "identifier": "id",
  "label": "name",
  "items": [
    {
      "id": "id1",
      "type": "year",
      "year": "2018",
      "childItems": [
        {
          "id": "id0",
          "projname": "Project 1"
        },
        {
          .....
        }
      ]
    },
    {
          .....
    }
  ]
}

Dojo treegrid mostly shows this error message when it finds multiple items with the same id, so you want to make sure all "id" attributes in your "items" list have unique value. In my test setup I was able to load more than 20000 rows so most probably you have malformed data. Supply following option to grid to log any fetch related errors:

onFetchError: function(err, req){
    console.log(err);
}

Hope it helps.